Chapter 2
GROWING PAINS: ALLIANCE FORMATION AND THE ROAD TO CONFLICT IN KOREA

This chapter will discuss how problems and politics in the nascent alliances and alignments in both the communist and anticommunist camps affected security relations between the two camps in the first years of the Cold War. The uncertain and poorly defined nature of the U.S. commitment to its partners in East Asia undercut the credibility of the nation’s near-term threats and long-term assurances in coercive diplomacy. This combined with political maneuverings in the formative stages of the East Asian communist alliance allowed Kim Il-sung to convince Stalin and then Mao to support Pyongyang’s attack on South Korea. The communist aggression that started the Korean War was rooted in a combination of communist elites’ underestimation of the resolve and power of the United States to counter such an invasion in the near term and an inflated view of Japan’s likely future role in the security politics of the region after its full economic and military recovery from World War II. Political dynamics within the communist camp also contributed greatly to the outcome of war in Korea. The internal politics of a still weakly knitted security relationship between Moscow, Beijing, and Pyongyang was an enabling factor for Kim Il-sung’s invasion of South Korea. The weakest actor, Pyongyang, was able to gain support from its stronger partners for its aggressive strategy of national unification through force by manipulating Moscow, Beijing, and the relationship between the two.

EARLY U.S. COLD WAR STRATEGIES TOWARD EAST ASIA

Strongpoint Defense and the Drawing of Lines

George Kennan’s strongpoint containment strategy was a creative exercise of prudent realpolitik. It reflected a recognition of the limits of U.S. military power and the large number of security concerns that the Truman administration faced in the early–Cold War era. The strategy focused U.S. efforts on the defense and reconstruction of friendly, anti-Soviet centers of industrial power and the prevention of these and other resource-rich or geographically significant areas from falling under Soviet control. By logical association, it eschewed hard-and-fast defense commitments to areas considered to be peripheral to the Cold War effort for either economic or geographic reasons.¹ In East Asia, Japan was included in Kennan’s strongpoints, but neither Taiwan nor South Korea was so included, even though Washington cooperated with both in security affairs in the years prior to the Korean War. Of the various problems within the anticommunist camp prior to the outbreak of war in Korea in June 1950, none looms larger than the ambiguous and anemic nature of Washington’s security relationship with South Korea and Taiwan that flowed from Kennan’s logic. What is less commonly appreciated is that the still-incubating U.S.-Japan security alliance in occupied Japan also contributed to instability by sending unintended signals about both the short-term and long-term implications of that budding alliance for the communist camp.

At the time of Dean Acheson’s January 12, 1950, address to the National Press Club, the Truman administration was forced to work with a defense budget that was one-third the size it would become after the Korean War began on June 25 and then escalated into a Sino-American conflict in November of that year. Before the Korean War the American public was relatively reluctant to pay significant costs or take substantial international risks in the realm of national security policy. Regardless of the mobilizing rhetoric of the March 1947 Truman Doctrine regarding the defense of “free peoples everywhere,” the United States could not realistically create a global defense commitment to counter all forms of communist aggression in all places around the world. That is the main reason why in April 1950 Truman shelved NSC-68, the National Security Council’s dramatic call for a more expensive and assertive U.S. security policy. There was a broad consensus in the administration about the document’s prescriptions, but little sense that the requisite defense budgets, foreign aid allotments, and security commitments would be marketable domestically.²

Fully in the spirit of Kennan’s strongpoint strategy, Acheson’s Press Club speech included in the U.S. defense perimeter Japan, the Ryukyus, and the Philippines as an island defense chain off the Asian mainland. Conspicuously absent on his list were the Republic of Korea (South Korea) and the Republic of China (Taiwan), both of which had received Washington’s military assistance, including training by U.S. officers, and would receive additional military assistance in the following months. In the case of South Korea, Acheson would later state that he had no intention of downplaying the U.S. security commitment to Seoul, which he saw as an extension of the United States’ obligation to the UN to stem aggression.³ In the case of Taiwan, the decision to exclude was more clearly intentional. President Truman himself had stated just one week earlier that the United States would not involve itself in the Chinese Civil War across the Strait “at this time” and even excluded future arms sales to the KMT (the United States would reverse itself on the latter pledge in a matter of weeks and then on the former pledge at the onset of the Korean War).⁴ Whatever Acheson’s intentions were in crafting these two speeches, we now know that in communist capitals and in Seoul itself, the Truman and Acheson speeches were viewed as symbols of waning U.S. resolve in Northeast Asia.

Ambiguous and Weak Security Partnerships: Early U.S. Cold War Strategies toward South Korea before June 1950

Korea was not considered vital to U.S. national security interests at the time. With the exception of a military advisory group, U.S. forces were withdrawn from the Korean peninsula in June 1949. But Acheson was not just making excuses for a failed strategy when he said in retrospect that Korea’s exclusion from the Press Club speech did not mean its survival was considered unimportant before June 25, 1950. After the United States removed ground troops from South Korea in June 1949, Seoul continued to receive military and economic aid packages and a substantial military advisory group (KMAG) remained on the ground to train Republic of Korea (ROK) forces.⁵ Although Taiwan’s security and the Chinese Civil War received much more domestic attention in the United States than did Korea policy, on two occasions administration proposals for assistance to Korea drove Taiwan policy, rather than the reverse. In June 1949 and late January 1950 proposals for aid to Korea led to domestic political storms in Congress over Asia policy, especially relating to the “loss of China.” Fearing the threats that these congressional attacks posed to Korea policy and the precedents that they potentially held for legislative approval of other foreign policy initiatives, the administration felt compelled to adjust its preferred policies toward the Chinese Civil War.⁶

Despite the importance of Korea as a noncommunist Asian state and as a test for the young UN, Korea was not, as mentioned earlier, included in Kennan’s list of strongpoints. In fact, it was as much the nature of the all-out armored invasion of South Korea, together with memories of European and American weakness in the early phases of World War II, as it was the importance of the target that triggered the Munich analogy in U.S. leaders’ minds and led to a resolute U.S. military response under UN auspices.⁷ In addition to South Korea’s limited strategic value and the opportunity costs of a containment line drawn on the Asian mainland, the Truman administration was very concerned about entrapment in an unwanted war by Syngman Rhee’s government in Seoul. In fact, one reason for the United States’ limited military assistance to Rhee was the fear that Rhee would exploit larger amounts of aid to attack North Korea. This was hardly an unreasonable concern, as Rhee’s nationalist goals were not entirely different from those of Kim Il-sung.⁸ As William Stueck, author of several authoritative diplomatic histories of the Korean War, makes clear, each of the two Korean leaders wanted national unification under his leadership, but only one had the military might and international backing necessary to launch an invasion in spring 1950. Rhee’s government was supplied insufficient parts and ammunition to sustain combat for more than a few days.⁹ As a result, the ROK was rendered militarily weaker on the defensive in 1950 precisely at a time when deterrence was weakened diplomatically by other aspects of the U.S. “strongpoint” strategy, including the limited U.S. military presence in the region and the withdrawal of military forces from the Chinese and Korean Civil War theaters.

Early U.S. Cold War Strategies toward Mainland China and Taiwan

Many leaders in the Truman administration, particularly in the State Department, would have preferred establishing formal relations with the CCP fairly soon after the communist victory in the Chinese Civil War on the mainland and the founding of the People’s Republic of China there on October 1, 1949. Beijing’s insistence on sole recognition of the PRC, however, would require Washington to abandon a World War II ally, Chiang Kai-shek’s Republic of China (ROC), the military and civilian government of which had fled from the mainland to Taiwan. Many favored such a move in Washington and had favored curtailing military assistance and other aid programs offered to Chiang Kai-shek’s KMT as that government progressively lost control of the Chinese mainland in 1948–49. One problem with this strategy was that it contradicted the administration’s spoken anticommunist justifications for economic and military aid policies elsewhere, and thereby threatened public and congressional backing for core policies in other areas. Complicating matters further, in 1949 Chiang’s forces had fled to the relatively easily defended island of Taiwan, and so assisting Chiang did not seem particularly risky or expensive on its face; therefore geography, together with the anticommunist underpinnings for the administration’s global strategy, made the abandonment of Taiwan hard to justify to the American public. Despite these problems, until the outbreak of the Korean War, the Truman administration seemed to have every intention of allowing Taiwan to fall to communist forces without American intervention. Although it hardly would have been considered a positive development in and of itself in Washington, Taiwan’s fall would have allowed the United States to extract itself permanently from the Chinese Civil War, avoid entrapment by Chiang Kai-shek in a war with the Chinese mainland, and thereby increase the potential for a future Sino-Soviet split along the lines of Marshal Tito’s Yugoslavia. Such a chain of events would also have allowed Washington to begin to coordinate more closely its China policy with Great Britain, America’s most important global ally and a nation that would recognize the PRC formally in early 1950.¹⁰ In this context, on January 5, 1950, Truman announced his intention to remove the United States fully from the Chinese Civil War across the Taiwan Strait.

Before June 25, 1950, the Joint Chiefs of Staff and the National Security Council concluded that Taiwan was of considerable strategic importance but was not “vital” to U.S. national security interests.¹¹ This designation of Taiwan as “less than vital” allowed Acheson to push through his still-controversial position that defending the island at the expense of long-term strategy toward mainland China and the region was not worth the candle. Despite Acheson’s policy preference, the United States continued to recognize the regime in Taipei as the sole legitimate government of all of China and continued to grant it economic and military assistance during the first half of 1950. Some of these continued aid packages and policy initiatives were rooted in domestic politics of the early Cold War.¹² In addition, Taiwan was still considered of some strategic value and nobody truly relished its collapse, even as it was anticipated.¹³

After the signing of the Sino-Soviet defense pact in February 1950, some in the U.S. government argued that the value of Taiwan to the United States had risen. Advocates of this position saw the island as a geostrategic base from which to counter the perceived Sino-Soviet monolith and as a symbol of U.S. resolve that could reassure Japan and others about the value of friendship with the United States during the Cold War. There is no evidence that these arguments won the day before the Korean War broke out, while there is much evidence that they did not.¹⁴

The United States did indeed care about Taiwan’s ability to fend off absorption from the mainland but was unwilling to make a strong and clear alliance commitment to the island in 1950. In addition to the fear of permanently alienating the Chinese communists by such a commitment, there was a legitimate concern that Chiang Kai-shek’s government would attempt to drag the United States into an unwanted war with mainland China. Here we see a parallel between U.S. leaders’ concerns about being dragged into war by a security partner and future ally in South Korea and their concerns about becoming embroiled in the aggressive policies of Chiang Kai-shek, another anticommunist irredentist involved in a bitter civil war.¹⁵ ROC forces had continued to bomb mainland China’s urban targets, often with American planes showing remnant U.S. markings, and to harass mainland ports with navy vessels transferred from the United States. This was a source of great frustration to the United States, especially to Dean Acheson, who was trying to get his country out of the Chinese Civil War, while Chiang was apparently trying to drag it back in. Chiang was simply ignoring State Department warnings and, according to Acheson, was “telling us to go to hell.”¹⁶

American strategy toward Taiwan would fundamentally change once the Korean War started and the U.S. Seventh Fleet symbolically entered the Taiwan Strait with the purpose of preventing aggression from either side. After the Korean War escalated into a direct Sino-American conflict later in the year, these changes became rather fixed. Korean War escalation destroyed any subsequent prospect for U.S. rapprochement with Beijing or distancing from Taipei.

As we will see later in the discussion of communist calculations, U.S. fear of entrapment and a desire to encourage divisions within the communist alliance over time led Washington to signal weakness about its support for Asian anticommunist forces, particularly those facing compatriots on mainland Asia in China and Korea.

Early U.S. Cold War Strategies toward Japan: America’s Reverse Course of 1948–51

U.S. policies toward Seoul and Taipei in the months leading to the Korean War have understandably received the lion’s share of scholarly attention in analyses of deterrence failure on June 25, 1950. A less-appreciated factor in the breakdown of coercive diplomacy is the destabilizing effect that signals sent from the budding U.S.-Japan alliance had on Soviet and Chinese calculations related to Korea during 1949–50.

Japan was always considered an important industrial power in the early Cold War years by U.S. grand strategists such as George Kennan, George Marshall, and Dean Acheson. However, in the first year of the Cold War (1947–48), a concerted effort to rebuild Japanese power was delayed. Since V-J Day in August 1945, Washington had given priority to General MacArthur’s efforts to restructure Japanese politics and economics so as to prevent either a return to militarism or a turn toward socialism. For this purpose, MacArthur’s occupation regime purged from politics many wartime leaders, instituted land reform, and began breaking down Japan’s large corporate conglomerates (zaibatsu or keiretsu). This strategy would begin to change in late 1947 and early 1948 with what diplomatic historians label “the reverse course.” As fears of the Soviet Union grew in Washington, concerns also grew that MacArthur’s reform program was making Japan politically unstable, economically weak, vulnerable to subversive political infiltration, and militarily unable to defend itself or assist in anticommunist efforts elsewhere. Washington, therefore, adopted a more politically and economically conservative program designed to stabilize the Japanese political economy. Many, especially officials in the Department of Defense, hoped that this would set the stage for increased Japanese military strength and burden-sharing in the future. Japanese national power, it was argued, would assist American efforts in countering international communism in Japan and the rest of East Asia.¹⁷Especially after the outbreak of the Korean War, this view would win the day in Washington, and it would be presented in Tokyo by Truman’s special envoy to Japan’s government, John Foster Dulles, in preparation for the turnover of sovereignty.

Despite concerted efforts to get Japan to do more on the military side, the United States agreed to compromise with Tokyo and accept much smaller Japanese military contributions to the alliance than were preferred in Washington. In the 1950s, the Truman and Eisenhower administrations both believed that Japanese discrimination against certain American imports, the systematically undervalued yen, and the reliance on American military protection were necessary to strengthen Japan domestically and internationally as an anticommunist ally. After much persuasion by Prime Minister Yoshida Shigeru, American leaders also decided that pushing the Japanese government to build up its military significantly and thereby reduce the American defense burden could lead to a popular backlash in Japan that might threaten the budding alliance and, by association, the maintenance of American bases in Japan.¹⁸ The Japanese authorities thereby resisted American pressure. The biggest source of frustration in Washington was Tokyo’s refusal to meet American targets for Japanese troop strength. In his advisory capacity, in 1950 Dulles had argued to State Department officials for a significant Japanese military buildup.¹⁹ Japanese leaders seemed to be able to fend off American demands for a larger and more active military by pointing out that socialists and communists waited in the wings to overthrow the conservative postwar coalition. The gap between American desires and Japanese realities were marked. For example, in 1951 Japan agreed to supply only about one third of the troops requested by Washington for its euphemistic “National Police Reserve.”²⁰ In the 1954 Mutual Security Agreement, Japan agreed to only one half of the total self-defense forces prescribed by Washington.²¹ This is not to imply that the U.S.-Japan security relationship was all a one-way street. The United States gained much from the Cold War relationship with Japan, as it does from its cooperation with Japan today.²² The most obvious U.S. benefit has been Japan’s willingness to serve as an invaluable base for U.S. power projection forces. This arrangement has cost relatively little to the U.S. taxpayer.

Especially given the legacies of the recent Pacific War and the generous American aid, trade, and military policies that Washington had already granted to Tokyo, the Truman administration was concerned about the domestic marketability of the budding U.S.-Japan alliance in the United States. Yoshida, therefore, would be pushed to accept Washington’s pro-Taiwan and tough anti-CCP China policies. American elites worried that if Yoshida diverged too sharply from the anticommunist strategies being advocated by the United States, the American Congress and public would demand a fundamental reconsideration of the already controversial relationship.²³ This concern was not unique to America’s Japan policy. Washington presented the same line to foreign leaders around the world as a reason for them to reconsider independent policy lines toward the communist world.²⁴

Judging from a careful analysis of the rather fickle nature of American public opinion on Cold War issues during 1947–50, the Truman administration’s argument to foreign leaders was not just a bill of goods. Although principled isolationism was relatively rare after Pearl Harbor, popular attitudes about the Cold War effort were hardly steady, swinging from dangerous levels of apathy toward international affairs, to dangerous levels of righteous anger toward the communist bloc and anyone in the domestic and international arena who seemed “soft” on communism.²⁵

American domestic politics in 1950 did much more than constrain the United States in its China policy. It made it impossible for the Truman administration to support any new apparent accommodation of the Chinese communists on the part of America’s key allies, including Britain and Japan. For example, in early December 1950, Acheson and Truman would shoot down British proposals for London to promote early peace negotiations in Korea, arguing that any accommodation by the United States of the Chinese communists that appeared to result from pressure by America’s allies would undercut American popular support for the global containment effort under NSC-68 and would lead the American public to reject further security assistance to all allies that broke ranks with the United States in its struggle against Asian communism.²⁶

In 1950–51, John Foster Dulles, as President Truman’s special envoy to Japan, would apply the same logic to U.S. dealings with the Japanese leader, Yoshida. Dulles made various arguments why Japan should reject Beijing as a diplomatic partner, recognize Chiang Kai-shek’s regime on Taiwan as the sole legitimate government of all of China, and sign a peace treaty with the ROC, rather than the PRC. Dulles also sought Yoshida’s general compliance with American limits on trade contacts with the PRC. Like most Japanese elites, Yoshida was very anticommunist. But as a practical matter, Japan wanted diplomatic ties with Beijing and much more extensive trade relations than Dulles’s preferred scenario would allow. As Yoshida bluntly put it, “I don’t care whether China is red or green. China is a natural market, and it has become necessary for Japan to think about markets.”²⁷ In his effort to persuade Japanese leaders to toe the U.S. policy line, Dulles’s trump card was not a straightforward geostrategic argument but a domestic political one with geostrategic implications. He emphasized that, if Japan did not comply with America’s general Cold War strategy, the American Congress and the American public would not support the Peace Treaty with Japan. Under such conditions, the military protection of Japan by American forces would become more controversial domestically, as would economic aid and Japan’s preferential trade and financial arrangements. It appears that it was this domestic political argument, above all others, that convinced the reluctant Japanese that questioning the American leadership role in the Cold War in Asia could carry devastating results for the recovering nation’s security and economic interests.²⁸ Dulles would return to this tried-and-true bargaining tactic again as President Eisenhower’s Secretary of State in order to prevent Japan from establishing politically significant trade offices in China.²⁹

To understand the sacrifice that Tokyo had to make in order to grant the United States a firm leadership role on the budding alliance’s China policy, it is critical to note just how important the Chinese economy had been to Japan in the recent past. As Michael Barnhart points out, it was partially the perceived need in Tokyo for a secure economic relationship with China that fueled Japanese aggression on the mainland in the 1930s. According to Barnhart, the inter-war Japanese leadership was actually obsessed first and foremost with the threat from the Soviet Union and the lessons of World War I about the need for an autarkic economy to provide staying power in war. The quest for Japanese autarky on the Asian mainland helped drive Japan deeper and deeper into a quagmire in China and, eventually, into war with the United States.³⁰ In the 1920s and for most of the 1930s, China (including Manchuria) was by far Japan’s biggest export market and import provider in the region.³¹

Not only would normal relations between Tokyo and Beijing facilitate business contacts, which were much more likely to be viewed as separate from politics by Japanese leaders than American ones, but also the arrangement would allow the new postwar Japan to seem less abrasive among the new Asian postcolonial nationalist movements that Japan’s militarist predecessors helped create.³²Yoshida’s desire to establish relations with Beijing after the founding of the PRC did not necessarily mean, however, that he was eager to break relations with Taiwan or that he would have been indifferent to a PRC invasion and takeover of Taiwan. In fact, in spring 1950 when Dulles, then a Republican consultant to Secretary Acheson, and Dean Rusk, then Assistant Secretary of State for Far Eastern Affairs, were trying to convince Truman and Acheson to reverse their policy of aloofness toward the Chinese Civil War and to agree to defend Taiwan, one of the most powerful sections of their appeal was a reference to an early May 1950 discussion between Japan’s Finance Minister Hayato Ikeda and Joseph Dodge, an American official in the Department of the Army. Ikeda, claiming that he was representing Prime Minister Yoshida, emphasized that many in Japan had come to doubt that the United States would defend Japan. One reason for this skepticism was the apparent lack of commitment of the United States to Korea and to Taiwan. In the Taiwan case in particular, the arguments within the American government about the island’s limited strategic importance seemed to carry direct implications for Japanese observers about the strategic status of the island nation of Japan in the eyes of the Americans. Ikeda was clearly asking the United States to take a firm position somewhere in East Asia so as to reassure Japan that America’s commitment to his recovering nation was a firm one.³³

Within the U.S. government there were two very different interpretations of the relationship between Taiwan and Japan’s security. To some U.S. elites, including Dulles and Rusk, Ikeda’s statement signaled that Japan desperately wanted Taiwan to be defended by the United States. If Taiwan were not defended, they believed, Japan would lose faith in America’s resolve in the region. Dean Rusk presented this position to Dean Acheson in an important policy memo on Taiwan.³⁴

But this was not the only reading of the Japanese position. On May 19, the State Department Office of Intelligence Research presented Acheson with quite an opposite reading of the Japanese attitude about Taiwan’s importance. The analysts argued that the fall of Taiwan would have a minimal impact on Japan’s economy, and would open the door for Japan to restore critical trade relations with mainland China. More important, the document states, “The Japanese appear to accept what they interpret as the American appraisal of the strategic value of Taiwan [that it is not vitally important]. The fact that the U.S. officially disclaimed any intention of defending Taiwan precludes loss of U.S. prestige in Japan as a result of Taiwan’s fall.”³⁵

It is possible to explain why two different U.S. government documents could draw such different conclusions about the Yoshida government’s position in May 1950. One group of analysts believed that Ikeda’s statement about the need for a tougher American posture meant that the fall of Taiwan would be viewed in Tokyo as a sign of failed American resolve. Another group may have seen the same statements only as a concern that the same measure of strategic significance given to Taiwan (less than vital to American security) could also be applied to the islands of Japan. For this latter group the solution was not for the United States to reverse its decision on Taiwan’s importance and decide to defend it. Rather the United States needed to reassert its commitment to Japan, and to demonstrate, through some concrete action, that Japan would not be labeled peripheral and abandoned to communist pressure. Supporting this interpretation is evidence of Yoshida’s own rather fatalistic attitudes about the future of Taiwan at this time and his general desire to prevent Japan’s Taiwan policy from undercutting efforts to improve relations with the mainland.³⁶

Japan’s acquiescence to American demands resulted in the December 1951 Yoshida Letter and subsequent bilateral Peace Treaty negotiations with Taipei in 1952, which locked Japan into a pro-Taiwan, anti-Beijing diplomatic posture for the next twenty years. With Japanese acceptance of America’s harsh economic sanctions regime against China, the small-scale but promising trade between Japan and the PRC allowed by the United States in 1949–50 practically disappeared.³⁷

From the perspective of alliance maintenance, the burden-sharing arrangement between Washington and Tokyo made a great deal of sense. But from the point of view of international strategy toward the enemy camp, the situation was hardly ideal. Obviously, having Tokyo and Washington on the same page made it more difficult for the communists to drive a wedge in the budding alliance and made it easier for U.S. administrations to sell at home the domestically controversial economic and alliance policies with Japan. But there were also large costs. Beijing noticed Japan’s hostile diplomatic stance but, as noted later, CCP elites were not particularly reassured by Japan’s unwillingness to play a larger military role. For much of the Cold War, Japan’s restraint on military security affairs was generally viewed as temporary and mercurial in Beijing. The prospect of future Japanese military assertiveness in Asia in alignment with the United States, Taiwan, and others was a fairly consistent concern of PRC strategists, even if on several occasions Beijing took some comfort in its overestimation of U.S. dependence on allies like Japan and Germany.

To be fair to the Asian communist elites on this one score, in 1949–50 it would have been nearly impossible to predict the persistence of the rather unusual U.S.-Japan defense relationship that we have witnessed since the early 1950s. But for our purposes, the United States’ bargain with Japan produced a bad mix of factors for coercive diplomacy. As we will see in the following sections, U.S. efforts to encourage Japanese industrial reconstruction and eventual military strengthening and Washington’s efforts to limit any rapprochement between Japan and the Chinese communists exacerbated fears in the communist world of an aggressive, anticommunist Japanese military presence in Asia in the future (especially in Korea and Taiwan). This impression in Moscow, Beijing, and Pyongyang would help tighten the Sino-Soviet alliance, and encourage Moscow and Beijing to give robust military aid to the North Koreans before the Korean War. While it fed such destabilizing reactions, the U.S. “reverse course” did not produce much in the way of actual near-term Japanese military power. So, the U.S.-Japan security relationship in 1949–50 was therefore quite poor from the perspective of bolstering U.S. coercive diplomacy in the region. Japan’s weakness and reluctance to play a larger military role early in the Cold War meant that the U.S.-Japan proto-alliance did not significantly enhance the deterrent threat of effective anticommunist intervention in Korea or Taiwan in the short run.³⁸ At the same time, from a longer-term perspective, the U.S.-Japan relationship served to undercut reassurances to the enemy camp about the future, creating fears of potential South Korean offensives and the growth of a powerful and aggressive U.S.-Japan-Korea alliance. These factors contributed to the communists’ decision to strengthen Kim Il-sung’s military in 1949, largely for defensive purposes. Then, when the balance seemed to turn in Kim’s favor in 1950, concerns about Japan’s future role in Asia made the Soviets and mainland Chinese more willing to agree with Kim that he should finish the job of unifying Korea on his terms before the regional balance of power turned against the communists.

THE FORMATIVE YEARS OF THE COMMUNIST ALLIANCE SYSTEM IN ASIA

Mao and Stalin: China Crosses the Yangzi (Yangtze)

After victories throughout the northern half of mainland China, in early 1949 forces of the Chinese People’s Liberation Army (PLA) were preparing to cross the Yangzi River to seize the KMT capital at Nanjing and to then unify the country by force. The more globally oriented Soviets were quite nervous about the CCP launching such a campaign, fearing the possibility of U.S. intervention and the overextension of PLA forces. The big fear in Moscow was that the Chinese Civil War might escalate, endangering the CCP’s victories to date and, perhaps, eventually dragging the Soviet Union into the Chinese Civil War.

The Soviets had much to lose by early 1949, having already insured a friendly government in northern China, an area where Moscow coveted raw materials and warm-water port access near the Soviet border. One might speculate that Stalin preferred a divided China to one unified under communist rule, but there is little evidence to support such a position. It seems more likely that Stalin’s cautious attitude in spring 1949 was underpinned instead by a combination of risk aversion, satisfaction with what the CCP had secured to date, and remnant condescension toward his Chinese communist brethren. In any case, in January 1949, Stalin and Mao exchanged rather frank messages debating whether or not the CCP should agree to negotiate with the KMT or simply drive south and finish the job by force. Mao rejected the idea of negotiations with the KMT and resented the Soviets’ offer at mediation in the Chinese Civil War. In addition, Mao clearly decided on his own to go forward with the crossing of the Yangzi, quickly seizing Nanjing in April and unifying most of the eastern portion of what is now the PRC by summer’s end.³⁹ As would become a pattern, local communists seeking unification of their nations under their own rule were more aggressive than the more cautious and satisfied Soviets, who were giving Mao’s followers advice from a safe distance and from a less parochial perspective.

This difference of strategy between Stalin and Mao colored not only their future relations but also Mao’s own attitudes about his responsibilities as an international revolutionary to support leftist national “liberation” struggles, particularly those movements seeking to avoid permanent division of their countries. Mao’s experience in the first half of 1949 would almost certainly influence his later attitudes about the Korean War. For his part, Stalin also seemed to learn dangerous lessons from the Chinese crossing of the Yangzi. Up to that point he had clearly been overly passive in his support for the Chinese communists’ efforts at national unification and had overestimated the danger of U.S. intervention and anticommunist resistance. In the months immediately after the crossing, Stalin would promise more energetic assistance to and deeper political relations with the Chinese communists in the future. For example, Stalin volunteered assistance in certain military areas, such as Soviet help in the creation of a Chinese communist air force.⁴⁰ A CCP entourage headed by the high-ranking Communist Party leader Liu Shaoqi secured these promises from Stalin on a trip to Moscow in early summer 1949. During Liu’s trip, Mao would announce in Beiping (later, Beijing) his “Lean to One Side” policy of joining the Soviet camp in the Cold War. Although a formal alliance between the CCP and the USSR was out of the question until the CCP finished the Civil War against the KMT and founded a communist state in China (which would occur on October 1, 1949), the Liu visit certainly set the CCP on course toward the December-February 1950 treaty negotiations between Beijing and Moscow.

During the visit of Liu’s entourage Stalin made clear his position that Mao’s CCP should support and guide Asian revolution.⁴¹ As events in Korea would demonstrate, despite Stalin’s language of putting the CCP in charge of East Asia, Stalin’s gesture had little to do with Stalin’s sincere desire to cede leadership to Mao. Rather Stalin was most likely interested in limiting the burden on the Soviet Union in an area of marginal importance to Moscow by passing the buck to his Chinese “comrades.”⁴² In a sense, Stalin did not have a tremendous amount of choice in the matter, as the Soviet Union lacked power projection capability in the Pacific until the 1970s and was busy rebuilding its economic heartland in Europe after World War II. Outside of the nearby Korean peninsula, Stalin really required Mao to pick up a share of the burden of supporting Asian revolutionaries loyal to the international movement that he led.

Mao’s and Stalin’s Attitudes toward the United States, Japan, and Korea

For the purpose of understanding the interactions between the U.S.-led system in East Asia and the communist alliance, it is most important to note how Mao’s and Stalin’s attitudes toward the U.S. presence in the region evolved in 1949–50. These attitudes would affect their views on whether or not Moscow and Beijing should support Kim Il-sung in his repeated proposals to unify the Korean peninsula by force. Such a decision would be based on what opportunity costs a war in Korea might carry for the regional communist movement.

For his part, Mao grew increasingly confident throughout 1949 that the threat of U.S. intervention in the Chinese Civil War was declining with each CCP victory and each KMT defeat. In January 1949, he warned the CCP Central Committee against “the mistaken viewpoint which overestimates the power of American imperialism.” While not dismissing the threat of U.S. intervention in the civil war, Mao emphasized that “as the Chinese people’s revolutionary strength increases and becomes more resolute, the possibility that the United States will carry out a direct military intervention also decreases, and moreover, in the same vein, the American involvement in financial and military assistance to the KMT may also decrease.”⁴³ In a telegram to Stalin in the same month Mao also called into question U.S. staying power in its support of the KMT.⁴⁴ In April, after crossing the Yangzi, Mao anticipated that the United States would not only distance itself from the KMT, but would also begin to consider ways to establish diplomatic relations with the CCP regime. Although he was willing to consider such relations with the United States in spring 1949, he would offer no concessions and would demand a total break between Washington and the KMT as a prerequisite, in line with Stalin’s own suggestions to Mao on the matter.⁴⁵

Of course, in negotiations with Stalin for assistance, the CCP would emphasize the need for Soviet help in guarding against the prospect of future U.S.-led imperialism in the region. A remilitarized Japan would play a central role in such scenarios. For example, in early 1949, Liu Shaoqi expressed concern to Stalin’s China expert, Ivan Kovalev, that the Chinese communists might face a major offensive by the United States, Japan, and Chiang Kai-shek’s KMT.⁴⁶But Mao was actually more confident than Stalin that the tide in China was with the CCP and against the KMT and the United States. Washington offered no help to the KMT when the CCP crossed the Yangzi and seized Nanjing and Shanghai. Moreover, the United States and Britain even largely ignored the PLA’s attacks on the British naval ship the HMS Amethyst, during the Nanjing operation.

What was unfortunate from a South Korean perspective was that the KMT was collapsing without U.S. intervention precisely at the time that the United States was preparing to pull troops out of South Korea as well. In April and May 1949 the Soviets were receiving intelligence from South Korea about the U.S. preparations to withdraw in the coming months.⁴⁷ The U.S. reputation for resolve to intervene in Asian civil wars was, therefore, weakening in Beijing and Moscow, with dangerous implications for Seoul. This perception of U.S. lack of resolve would only be reinforced in January 1950 with the delivery of President Truman’s speech on U.S. policy toward the Chinese Civil War and Acheson’s National Press Club speech, which seemed to indicate that any U.S. commitment to South Korea or Taiwan had been abandoned.

What was ironic about Soviet, Chinese, and North Korean estimations of U.S. withdrawal from Korea in 1949 was that, in the near term, the event did not reduce their sense of threat from their enemies. In important ways it increased that sense of threat. Given the perceived weaknesses of North Korea at the time, the apparent aggressiveness of the South Korean deployments along the 38th parallel, and persistent fears of Japan’s reentry into the Korean theater at a later date, the communist capitals did not take great comfort in the prospect of U.S. withdrawal, at least not at first.

All three communist capitals seemed concerned that a U.S. exit from Korea would unleash Syngman Rhee’s government in South Korea to launch offensives against the North, perhaps with eventual assistance from Japan. As stated earlier, this could not have been further from an accurate read of the U.S. intention in the withdrawal. Declassified telegrams in the Soviet Archives demonstrate the concern for North Korean vulnerability in both Moscow and Beijing at the time. North Korean leaders told their quasi-allies that they feared attack from South Korea and Japan after U.S. withdrawal.⁴⁸ Kim Il-sung played on Stalin’s concern regarding Japan when emphasizing the dangers posed by the U.S.-backed South Korean government and the need, with Soviet help, to unify the peninsula under communist control. According to Kathryn Weathersby, Stalin in particular believed that Japan, with U.S. backing, would rearm and eventually use a base in Korea as a threat to the Soviet Far East. Only Stalin’s remaining concern about direct conflict with the United States in the near term would prevent him from accepting Kim’s bait by approving such an invasion.⁴⁹ Stalin apparently took Kim’s prognosis very seriously, viewing June 1949 as a period of high danger for such a South Korean invasion of the North.⁵⁰ Beijing in particular was very concerned about the threat of large-scale Japanese intervention in a protracted Korean conflict. Soviet reports from Pyongyang indicate that in a meeting with an emissary of Kim Il-sung in Beijing in early May, Mao said the following:

The U.S. alliance policy of withdrawing troops in 1949 from South Korea only stoked Beijing’s and Moscow’s concerns about the threat to North Korea, because it would free up local actors for aggression. Kim was able to parlay these concerns into increased assistance from his foreign communist supporters.

Pyongyang would procure most of its military equipment and training from the Soviets, who also kept over 1,000 advisors in North Korea after Soviet troops left in early 1949.⁵² North Korea also requested from China the transfer or repatriation of ethnic Korean troops fighting in the Civil War along with their weapons and ammunition. Mao would agree to the transfer of two of these three divisions in May 1949 (the third was already engaged in offensive operations in southern China and was, therefore, unavailable at the time).⁵³ In early January 1950 while Mao was in Moscow negotiating the Sino-Soviet Treaty, Beijing and Pyongyang would agree to the transfer of an enlarged third division of ethnically Korean troops (some 14,000–16,000), the most experienced and battle-hardened of the three divisions to be sent to Korea. ⁵⁴ Chinese military historian Xu Yan and diplomatic historian Shen Zhihua argue that these transfers in 1949 and 1950 were ordered by Mao to help the North Koreans defend against future invasion from South Korea and Japan, not to encourage the North to launch an attack themselves.⁵⁵ This seems quite plausible, at least for the 1949 transfers. In the end, however, this assistance would not be used for defense of the North against invaders, but in the North’s invasion of South Korea in June 1950. The three ethnically Korean divisions transferred over the past year would eventually spearhead the invasion.⁵⁶ Moreover, the changed intrapeninsular balance between spring 1949 and January 1950 seemed an important element in Stalin’s decision to reconsider his opposition to Kim Il-sung’s disastrous plan to attack the South.⁵⁷ Despite the significance of this Chinese transfer of troops, the more powerful Soviets provided much more assistance to the North than did Beijing and clearly had the stronger influence on Pyongyang.

On at least three occasions (March 1949, August–September 1949, and January 1950) Kim Il-sung had requested from Stalin approval and support for an attack on South Korea (and on at least two occasions Pyongyang also approached Mao). Until late January 1950 Stalin refused to back such an adventure fearing both local failure against anticommunist forces that he perceived as superior and the potential for escalation of the war to involve the United States. The more cautious Stalin encouraged North Korea instead to adopt defensive measures and build up its military to improve the local balance of forces in its favor.⁵⁸

In March 1949 Kim Il-sung initially approached Stalin with a request for help in a military offensive to unify the peninsula under his leadership. This notion was rejected almost out of hand by Stalin as the peninsular balance of power seemed to favor the South and the United States had not yet withdrawn forces from South Korea. For his part, Mao rejected the idea of a North Korean invasion of South Korea in May 1949, citing his concern about the North’s inability to win relatively quickly. Mao was worried that an attack in 1949 would be premature given the international situation at the time. Mao apparently believed that the South still had the upper hand in the peninsular balance of power, particularly when one factored the prospect of Japanese reinforcements into the equation, as Mao consistently did.⁵⁹ A document in the Soviet archives suggests that Mao shared Kim’s concern that Japanese forces might replace U.S. forces in the South following the expected U.S withdrawal later that spring. Mao believed that Japanese forces could then assist in an invasion of the North. Mao advised that North Korea prepare to counterattack such an invading army. But he added that the North Koreans would need to be cautious especially if the Japanese were involved directly in the future invasion. In that case, Pyongyang should be willing to sacrifice some land to the enemy in order to gain a better military position, surrounding the enemy troops and annihilating them later. Mao stated that Chinese troops could then eventually help the North Koreans defeat the Japanese army.⁶⁰ A Soviet document quotes Mao as saying, “Even under conditions where the Americans go and the Japanese do not come [to replace them], we still advise the Korean comrades not to launch offensives against the South but to wait for a more propitious situation.”⁶¹ The time was not ripe for a North Korean attack in the minds of the leadership in Moscow and Beijing. One key reason was that CCP elites, still caught up in their own civil war, believed that the Chinese communists would have great difficulty lending support to North Korea as quickly as the United States could support South Korea, perhaps by sending in divisions of Japanese soldiers to fight there.⁶²

In general, Mao believed that North Korea and China in combination could defeat a South Korean and Japanese condominium on the peninsula, but he was not itching for a fight and did not believe in May 1949 that the balance of forces favored the communists.⁶³ It was in this more defensive context that Mao agreed to the transfer of experienced troops and their equipment from China to North Korea. Ominously for the anticommunist forces in the region, in spring 1949 Mao suggested that by early 1950 the situation might have changed for the better from the communists’ point of view and the communists could revisit this issue.⁶⁴

In August and September 1949, the Soviets again would reject the idea of a North Korean invasion of South Korea, which was apparently raised by Kim Il-sung on August 12. In late August the Soviet ambassador to Pyongang, Terentii F. Shtykov, cited South Korea’s perceived relative military strength, the danger that the United States might send weapons to the South and dispatch Japanese forces there, and, rather presciently, the danger that the United States might use the occasion of a major North Korean offensive to launch a major international campaign against the USSR.⁶⁵ In draft instructions to the embassy in late September, Molotov stated that the Soviet ambassador to North Korea should “sternly and seriously” relay the message that the situation on the peninsula was neither politically nor militarily ripe for such an attack. The North still did not have “absolute superiority” on the battlefield and, combined with the lack of political preparation, would face a long war involving the United States. In an incisive analysis, Molotov surmised that an unsuccessful North Korean invasion could lead to a long-term U.S. military presence in South Korea under UN auspices.⁶⁶ In mid-October 1949, two weeks after the founding of the PRC, Mao and Stalin apparently exchanged notes agreeing that a North Korean attack on the South would be unwise. The North was advised to use guerrilla operations to weaken and destabilize South Korea and to continue with its own military strengthening at home.⁶⁷

The Tail Wags the Dog: Stalin’s Reversal on the North Korean Invasion

On January 17, 1950, at a luncheon in Pyongyang attended by the Soviet ambassador, Kim Il-sung again requested Stalin’s support and approval for an attack on South Korea. Kim emphasized that he had an opportunity to exploit South Korean popular opposition to the government there and garner backing in the South for himself. He requested a meeting with Stalin. He said that, as Stalin had suggested, he had waited for a South Korean attack on the North to provide a legitimizing pretext for a North Korean “counterattack,” but the South had not obliged him. Kim played well on Stalin’s combination of arrogance and insecurity, saying that, as a communist, Kim could not launch an attack by himself and that “Stalin’s directives were law,” in his mind. However, he added that if Stalin could not meet with him to discuss this matter, he, Kim, could meet with Mao in China after the latter’s return from the Soviet Union (Mao was in Moscow negotiating the Sino-Soviet defense treaty). Kim pointed out that based on what Mao had said in the past, he believed that the PRC leader would support such a plan after the completion of the war in China. Kim said that he had other issues to discuss with Mao in any case, such as the creation of an Asian Cominform. He added that Mao would have received all the appropriate directives in Moscow and could discuss the Korean proposal for an invasion with him. The North Korean president finished his discussion with a request for Stalin’s appraisal of the situation in South Korea.⁶⁸

Whether it was intended to play such a role or not, such talk from Kim could only have helped feed Stalin’s well-documented fears regarding Mao’s influence in Asia as an actor independent of Stalin’s control. Stalin had treated Mao with great caution when the latter arrived in Moscow to negotiate a defense treaty, delaying substantive talks for weeks. According to Odd Arne Westad, Stalin wanted to test Mao’s dedication to “proletarian internationalism” and to ensure Soviet territorial claims in the region.⁶⁹ Although the causal connection is not clear, once Stalin agreed to discuss the treaty in early January, Mao made decisions in Moscow that were consistent with an effort to demonstrate his revolutionary credentials to Stalin.⁷⁰ On January 8, Mao agreed to send the third division of ethnically Korean forces in the PLA to North Korea.⁷¹ Two days after Acheson’s January 12 “defense perimeter” speech, which was viewed in Moscow as designed to create a wedge between Mao and Stalin, Mao ordered the seizure of the U.S. consular property in China.⁷² On January 17–18 Mao ordered Beijing to recognize Ho Chi Minh’s government in Vietnam.⁷³ Whether these actions fully convinced Stalin of Mao’s dedication to proletarian internationalism is unclear. We do know from Russian sources that Stalin remained very concerned about Mao’s loyalty to Soviet leadership.⁷⁴ Given this concern, Stalin could not have been pleased with the idea of Kim Il-sung turning to Mao for leadership after Stalin had refused Kim’s requests regarding military unification twice in the past. Given the conspiratorial and zero-sum nature of revolutions, it is perhaps not surprising that revolutionary leaders in the Soviet Union and China would view each other with such deep mistrust, particularly in the early stages of forming strategic partnerships. Moreover, on an individual level, both Stalin and Mao were arguably unusually untrusting of comrades at home and abroad, even by communist revolutionary standards.

After determining that the international situation had changed over the previous months and after receiving some recent intelligence from South Korea about political instability and the low state of morale there, on January 30, 1950, Stalin decided to reconsider his earlier opposition to a North Korean invasion of the South and to discuss this issue directly with Kim in Moscow at an appropriate time. The Soviet leader’s reconsideration of the issue occurred while Mao and Zhou Enlai were still in Moscow negotiating the February 1950 Sino-Soviet defense treaty. But all indicators suggest that Stalin kept Mao in the dark about his changed plans for Korea. According to documents cited by Weathersby, and consistent with the foregoing analysis, on February 2, 1950, Stalin asked Kim not to discuss his forthcoming trip with his own colleagues or with the Chinese communists. Stalin cited security concerns and the sensitivity of the topic.⁷⁵ Kim arrived in Moscow on March 30 and would stay until April 25 to discuss his plan and secure a final blessing from Stalin.

What changed in Stalin’s thinking from September to January? Scholars studying the Russian and Chinese archives cite various factors. One very important factor was the U.S. withdrawal from the Chinese Civil War. Weathersby and others cite Stalin’s statements to Kim in March 1950 that he was reassured by the CCP victory in China and the lack of U.S. intervention during the KMT’s collapse.⁷⁶ A Party document from the Central Committee that is presented by Weathersby states the following:

Stalin then placed two critically important conditions on Kim’s invasion: “However, we have to weigh once again all the ‘pros’ and ‘cons’ of the liberation. First of all, will Americans interfere or not? Second, liberation can only be started if the Chinese leadership endorses it.”⁷⁸

Weathersby argues that, in addition to the signaling of U.S. weakness inherent in its withdrawal from the Chinese Civil War, a secret U.S. policy document on East Asia, NSC-48, had been passed to the Soviets by British spy Donald McLean.⁷⁹ There is little doubt that Stalin had a spy network in the United States, Europe, and Asia, but in this case access to NSC-48 might not have been necessary. The Truman administration was publicizing the key elements of its strategy. In a speech on January 5, 1950 Truman for all intents and purposes announced a permanent U.S. withdrawal from the Chinese Civil War, including the cessation of military aid. On the following day, Great Britain recognized the PRC. The issue of the importance of U.S. acquiescence to Chinese communist victory as a precedent in Korea is evident in the Soviet documentation and in the secondary histories.⁸⁰ Moreover, as noted earlier, Acheson’s National Press Club speech on January 12, 1950, excluded both South Korea and Taiwan from the U.S. defense perimeter. That speech revealed to the public the most important aspects of NSC-48 regarding U.S. intentions toward South Korea. Although the full weight of its importance in Stalin’s mind is not entirely clear, we know that Stalin and Mao discussed the speech during the latter’s stay in the Soviet Union to negotiate the Sino-Soviet Treaty.⁸¹ According to diplomatic historians studying both the PRC and the USSR, Acheson’s speech had an impact on Stalin and Mao and, along with the earlier Truman speech on Taiwan, may have contributed to Stalin’s conclusion that the likelihood of U.S. intervention in Korea was limited. Stalin apparently mentioned the speech to Mao and his entourage, characterizing it as an effort in Washington to drive a wedge between Moscow and Beijing and as part of a longer-term strategy to deny Taiwan to the PRC.⁸²

Finally, we now know from declassified Soviet documentation that in January 1950 Stalin had relevant intelligence from his spies in South Korea. These intelligence reports suggest that leaders in Rhee’s government also believed that the United States would not intervene to save them if they were to become embroiled in a war of unification. According to the January 28, 1950, Soviet intelligence report, South Korean elites were very concerned about the state of their economy, politics, and international backing. On the international front, ROK leaders listed three important factors: 1) South Korea was extremely unlikely to get help from the United States; 2) the United States would not help Chiang Kai-shek defend Formosa (Taiwan); and 3) Great Britain had recognized the PRC. They believed that the ROK would receive the same treatment as the KMT, that Britain would recognize North Korea next, and that the United States would follow suit in China and North Korea. Even before the Acheson speech, Syngman Rhee’s cabinet concluded that the United States was not willing to fight for South Korean interests. Rhee did not believe that the United States would write off South Korea entirely (as he believed Washington had just done to Taiwan) until after the issue of Japan was resolved, but he did not believe that the United States would fight alongside the South. His prescription was a diplomatic initiative to gain tighter coordination between South Korea, Japan, and the United States in a united anticommunist front.⁸³

Stalin received this information regarding South Korea just two days before his January 30 policy reversal on North Korea’s invasion of the South. The mixed message he received from Seoul about U.S. alliance policy could not have been worse from a deterrence point of view. On the one hand, its strategic decisions about where to defend and with whom to ally were making the United States seem weak in the near term in areas like South Korea. Moreover, South Korean morale appeared shaken at a time when the balance on the peninsula was moving in the favor of the North. On the other hand, while Japan was not yet ready to contribute greatly to South Korean security, the South Korean leader was discussing the need for closer collaboration with Japan in the future as a solution to the potential for abandonment by the United States. Rhee’s alignment strategy, which is in keeping with the theoretical work of Victor Cha on the later ROK-U.S.-Japan relationship, must have helped undercut both sides of a standard deterrence relationship for Stalin.⁸⁴ The anticommunist allies appeared temporarily weak and in disarray, inviting attack in the near term, but Seoul’s prescription for healing its woes played into Stalin’s fears about the future: the formation of a tight Korea-Japan-U.S. condominium after Japan had become politically independent and militarily more powerful.

Elizabeth Stanley argues that in early 1950 hawkish advisors in Moscow had been pushing exactly the same line as Kim regarding the future activities of the U.S. security partners in the region. She writes that

The uncertainties of U.S. alliance politics in the early Cold War managed to undercut both portions of a successful attempt at coercive diplomacy: credible threats and assurances. There were both insufficient threats to deter communist aggression in the near term, and insufficient assurances that near-term peace would provide longer-term security from a Soviet perspective.

In the first months of 1950, Stalin still had major concerns about the operation. He was simply not as confident as Kim that the victory would be quick or that the chances of effective U.S. intervention were quite so small. Stalin insisted on careful preparation, secrecy, and, eventually, securing of Chinese approval of the invasion after his meetings with Kim and Pak Hon-yong in Moscow. During their meetings, Stalin insisted to Kim that “liberation can be started only if the Chinese leadership endorses it.”⁸⁶ He also told Kim that Soviet forces would not be used in Korea if the invasion went awry. North Korea would have to rely on its own efforts and Chinese assistance. Kim replied by asserting that that the United States would not get involved; that Mao was fully supportive and had offered to help in the past; and that because the United States would not get involved, Chinese help would not even be necessary. Stalin reiterated that Kim should get Chinese approval, stating that, especially if the United States were to get involved in the war, China, not the Soviet Union would have to provide direct assistance. Kim insisted that, by the time the United States could digest the invasion and reverse course on its South Korea policy, the war would be over. Kim cited not only a distribution of military power on the peninsula that by spring 1950 would clearly favor the North, but he and Pak also predicted a massive uprising in the South in support of the North. They therefore posited that the war would end within a few days.⁸⁷

U.S. policies toward Japan, Chiang Kai-shek’s Republic of China, and South Korea all contributed to Stalin’s false sense in 1950 that a North Korean invasion of the South would be much wiser than it had seemed in 1949. But Stalin still appeared concerned about the potential risk of North Korean failure and the danger of escalation involving the United States. So, why did he approve of the invasion despite those concerns?

Judging from the writings of leading diplomatic historians in the United States, Russia, and China, Stalin’s suspicions about Mao’s potential Titoism or Asian Leninism assisted Kim Il-sung in his efforts to be the tail that could wag the communist international dog. For example, historians Vladimir Zubok and Constantine Pleshakov argue that knowledge of Mao’s likely future independence as a communist leader is “critical for explaining why Kim succeeded in getting Stalin to consent to the invasion of South Korea.” They write,

In an article based on Soviet archives, Weathersby speculates that Stalin approved of the North’s attack on the South in large part to guarantee that the PRC would not stray from Soviet leadership and in part to guarantee the Soviets’ relative prestige in the international communist movement.⁸⁹ This makes sense. By offering conditional approval for Kim’s invasion, Stalin was pushing Mao into backing an initiative for which Stalin could still receive the credit. If Mao refused to back Kim’s plan, Mao rather than Stalin could be blamed for balking and refusing to back the invasion.

A leading Chinese expert of Soviet diplomatic history, Shen Zhihua draws a somewhat similar conclusion about Stalin’s motives. He argues that Stalin in early 1950 did not trust that Mao would play the role of the vanguard (xianfeng) in allying with the Soviet Union and countering the United States. Moreover, Stalin feared being dragged into a war with the United States by any ally, especially over an issue in Asia, a theater of secondary importance to Moscow. Pushing for armed unification of Korea before he allowed China to take on Taiwan and doing so through conditional approval served both of Stalin’s purposes: avoiding World War III between the United States and the Soviet Union and assuring China’s allegiance and second-ranking status in the movement that he led. According to Shen, if the Chinese recovery of Taiwan were to have preceded the unification of Korea, Stalin would have had two worries. First, as a sea-and-air battle, where the Chinese were weak and the United States was strong, a fight over Taiwan was more likely to drag the Soviet Union into a war with the United States than a fight over Korea, in which Stalin could hope to pass the buck to the Koreans and Chinese fighting on land by merely supplying weapons. Second, China was not yet considered a trustworthy ally by Stalin in Northeast Asia, and if it were able to solve the Taiwan problem in the near term—before Korean unification—China would be more likely to go its own way, refusing to play the role of the Soviets’ main ally in Northeast Asia and potentially even becoming a threat to Soviet interests in East Asia. So, according to Shen, the conditional approval of a Korean invasion in May fit Stalin’s strategy perfectly. Such a formula allowed Stalin to avoid direct U.S.-USSR conflict, pushing China into an internationalist position, distracting it from Taiwan and thereby preserving China’s dependence on the Soviets for assistance on that issue. A Korean conflict in the near term solidified the Sino-Soviet alliance, and thereby better guaranteed Chinese loyalty to the Soviet-led movement. As Shen puts it, the outbreak of the Korean War was the first “great test” (da kaoyan) of the Sino-Soviet alliance, and the process leading up to it exemplified Stalin’s prewar lack of trust in Mao.⁹⁰

Shen’s account is consistent with other studies of Stalin’s thinking in early 1950 by Russian diplomatic historians. In the first half of January Stalin was allegedly quite concerned that the United States would settle its account with Beijing by abandoning Taiwan and thereby undercut the budding Sino-Soviet alliance. In fact, the speeches by Truman and Acheson were hardly all good news for Stalin on this score. By suggesting the prospect of peace between the United States and his potentially Titoist Chinese comrades even before a Sino-Soviet alliance was signed, Stalin reportedly worried that China might not stay on board with him.⁹¹ Mao’s own later recollections of Stalin’s attitudes at the time confirm this analysis. Mao said that Stalin did not fully trust him to be a real revolutionary until after China’s massive intervention in the Korean War later in the year.⁹²

Mao’s Alliance Dilemma: To Support or Veto?

Having gained Stalin’s conditional approval in April, Kim then traveled to Beijing in mid-May to seek Mao’s approval. Mao had apparently not been informed of any of the deliberations between Stalin and Kim, and the Kim proposal for an invasion came as a surprise. According to a document in the Soviet archives, in preparing for Kim’s trip to Beijing in May, Mao had told the North Korean Ambassador to China that Kim should come secretly if he was planning to attack the South in the relatively near future. Mao told the DPRK representative that, in general, he did not believe that Korea could be unified peacefully and he thought it impossible that the United States would “launch World War III over such a small piece of territory [as South Korea].”⁹³ It is important to treat this document’s contents with some suspicion, especially the report of Mao’s casual confidence about nonintervention by the United States. Kim was hardly beyond embellishing these points for Stalin’s ears at a time when the latter was still somewhat concerned about the threat of war with the United States and quite insistent that Kim receive the approval of Mao before he move forward. The portrayal of Mao that Kim’s ambassador gave to Stalin fit Kim’s plan perfectly: Mao agrees that we must use force to achieve our goals; he believes it will be absolutely safe to do so; and we have Mao’s full backing. This was likely all part of Kim’s quite successful plan to be the tail that wagged the communist alliance’s dog.

Along the same lines, judging from the Russian documentation, when Kim arrived in Beijing he strategically avoided mentioning to Mao the conditionality of Stalin’s earlier approval of Kim’s plan. He apparently did not inform Mao that Stalin would not back the plan unless Mao did as well, instead telling the CCP leadership that Stalin had agreed to Kim’s plan but simply wanted Kim to discuss the issue with Mao in person. Appropriately distrusting his Korean quasi-ally, Mao urgently sought clarification from Moscow. On May 13, 1950, Zhou Enlai visited Soviet Ambassador to China N. V. Roschin and asked him to cable Moscow immediately for clarification. The description of what Kim had told Mao and Zhou is telling and important, as is Stalin’s reply. On May 13, Roschin wrote, “This evening Comrade Mao Zedong met with their [DPRK leaders'] entourage. In discussions with Comrade Mao Zedong, the Korean Comrades notified [him] of the following directive from Filipov [Stalin]: at present the situation is different than it was in the past, North Korea may begin to take action; but, this issue must be discussed with Chinese Comrades and Comrade Mao Zedong himself.”⁹⁴ The following was Stalin’s reply the next day: “In meetings with Korean comrades, Filipov [Stalin] and his friends raised [the following], in light of [the fact] that the international situation has already changed, they agree with the Koreans’ proposal to realize unification. At the same time they added a point, this question must be decided in the end by the Chinese and Korean comrades in common. If Chinese Comrades do not agree, then we have to reconsider how to resolve this question. The details of the discussion can be related to you by the Korean Comrades.”⁹⁵ Stalin’s reply underscored that he was offering much more decision-making authority to Mao than Kim had initially reported to the Chinese leader.

In what is a major breakthrough in PRC scholarship, mainland historians now recognize in openly published sources some key facts never before discussed in public in the PRC: the North started the war; Mao and Kim met to discuss the invasion in advance; and Mao and Stalin exchanged telegrams that clearly placed the last chance at stopping the war on Mao’s shoulders by giving him veto power over Kim’s final decision. The same histories tend to insist, however, that Mao had very little or no room for maneuver in this situation, pinning the blame for the war on Stalin and Kim.⁹⁶ Weathersby agrees, stating that “Mao Zedong had little room to voice objections to the fait accompli presented by the Koreans.”⁹⁷ But, however difficult the situation might have been for Mao, Stalin offered him veto power over a decision that would be momentous in the history of Korea, the PRC, and the Cold War more generally. Mao decided to back Kim’s plan on May 15, 1950, in what was arguably the most important date in PRC diplomatic history. What is still not said (or not allowed to be said) in China is that Mao made a terrible blunder in deciding to approve the invasion, thereby starting a war that ended up where it started (at the 38th parallel) and that cost his country the long-term separation of Taiwan, hundreds of thousands of casualties, increased PRC dependence on Soviet aid, and decades of exaggerated hostility with the United States.⁹⁸

In my opinion Mao deserves a much larger share of the responsibility for the war than Weathersby and the PRC scholars allow. That said, when one considers the nature of the communist alliance system in East Asia and Mao’s reliance on the Sino-Soviet alliance for support to complete his own national goals, Mao was indeed in a tough spot. The PRC was a new ally of the Soviet Union, and, as discussed earlier, Stalin was suspicious of the CCP’s revolutionary credentials. Mao had reason to know this. In January 1950 Stalin apparently informed Mao of internal reports by Stalin’s main China advisor, I. F. Kovalev. Kovalev had fed Stalin’s suspicions about Mao’s loyalty to the international movement under Stalin’s leadership and hinted that Beijing was eager for a separate peace with the United States.⁹⁹ As previously discussed, while in Moscow in January 1950, Mao had made several orders to his colleagues in Beijing that seemed consistent with a desire to impress Stalin with his internationalist fervor. We saw a similar behavioral pattern in spring 1949. In May of that year, after Mao’s representative Huang Hua had been in contact with the U.S. ambassador, Leighton Stuart, Mao made a point of bringing Kovalev into a CCP Politburo meeting at which he would express his party’s lack of interest in diplomatic relations with the United States. He did this despite Stalin’s own April stamp of approval of eventual CCP diplomatic relations with the United States and the CCP’s continued outreach to Stuart through late June 1949.¹⁰⁰ The historians Sergey Radchenko and David Wolff conclude that “Mao clearly played a double game, bringing Stalin’s attention to the apparent U.S. willingness to recognize his regime, all the while claiming lack of interest in such an outcome to prove his revolutionary credentials to the Soviet leader.”¹⁰¹ If their analysis is correct, it seems quite plausible that a similar logic of impressing Stalin might have contributed to Mao’s decision to back Kim’s invasion in May 1950.

Mao could not afford to be seen as weak on revolution and anything but a seconding of Stalin’s conditional approval of Kim’s invasion plan would have made him appear so. Mao had also recently been on the receiving end of advice to put off national unification and to be cautious (in April 1949 at the Yangzi), and he did not want to be viewed internationally as short on internationalism or international fervor. He required not only economic and military assistance and training from the Soviet Union for his new country, but he had set for himself a difficult unification challenge of his own—taking Taiwan by force—which would require an extensive amount of help, particularly in building a navy and air force to fight across the Taiwan Strait, a process that the CCP had started in earnest in spring 1950 with Soviet help. Moscow was the only place to turn for such assistance at that time.¹⁰² Moreover, Stalin had been decidedly reluctant to support the concept of a PRC assault on Taiwan in 1949–50.¹⁰³

Available evidence suggests that Mao was more nervous than Stalin about the prospect that an invasion of South Korea could go poorly for Kim Il-sung’s forces. It is unclear why Mao would raise these points of concern in discussions with Kim and his entourage if Mao had planned to go ahead with Kim’s plans regardless of the perceived risks. In other words, Mao was hardly simply following orders from Moscow but was making his own calculation about the merits of Kim’s plan.

There is little doubt that there was a systematic underestimation of U.S. resolve and commitment to South Korea in all three communist capitals. No factor mattered more than this one in the disaster. But Mao did not share Kim’s drunken optimism about the war, at least not to the same degree. Instead, Mao apparently told Kim that the DPRK needed to prepare carefully. Consistent with Mao’s inflated concerns about Japanese military activism, Mao warned that a major Japanese contingent of tens of thousands of Japanese soldiers might enter the war over time.¹⁰⁴ Mao’s reported estimation for Korea was consistent with high-level military analyses in December 1949 of a future conflict across the Taiwan Strait: Chinese General Su Yu believed that the United States would stay out but that it might mobilize Japanese forces to help Chiang Kai-shek in a cross-Strait conflict.¹⁰⁵

In discussions with Mao, Kim called such intervention by the United States and/or Japan “improbable” but acknowledged that the United States might send a few Japanese divisions, which he was sure his forces could defeat. Mao replied that if Japan could extend the war, then the United States could later enter the war directly. Kim cleverly manipulated the lack of coordination between Beijing and Moscow by dismissing Mao’s fears about the United States with reference to Stalin’s own calculation that the United States would not enter into Korea because the United States had abandoned China! Kim then duplicitously told the Soviet ambassador that Mao believed Japan could not interfere and, if the United States were to interfere, Mao believed Chinese, not Soviet, troops should bear the burden!¹⁰⁶ Mao indeed offered to prepare a Chinese military response to the prospect of a Japanese intervention in Korea followed by a U.S. intervention, but Kim, who apparently never informed him of the timing of the invasion in any case, apparently believed tight coordination with Beijing over Chinese intervention would not prove necessary.

Mao’s blunder in spring 1950 occurred in large part because he was manipulated by both his weaker Korean ally and his stronger Soviet one. It also occurred in large part because Mao and Stalin misread the alliance dynamics of the enemy camp: underestimating the likelihood of robust, direct U.S. intervention and overestimating Washington’s reliance on the much less formidable Japanese. Many factors were at work in producing the outbreak of the Korean War. Among the most important were the unclear signals sent by U.S. security relationships with Korea, Taiwan, and Japan. In addition political dynamics within the budding communist alliance allowed Kim Il-sung to manipulate his more powerful allies into exploiting the perceived opportunities provided by weakness in the anticommunist camp, so they could attempt to revise the status quo by force before that camp could solidify its position on the Asian mainland.