Alliance Treaty as Wedge Strategy: The Origin of the China-North Korea 1961 Treaty of Friendship, Cooperation and Mutual Assistance

Abstract

What explains China’s decision to sign an alliance treaty with North Korea in 1961? The treaty was redundant to deter the United States and South Korea because China had credibly established its resolve and capability to defend North Korea after the outbreak of the Korean War in June 1950. The treaty even increased the risk of China’s entrapment in a Korean conflict. This article develops a triangular theory of alliance formation to show that China’s signing of the treaty was intended to drive a wedge between North Korea and the Soviet Union, not to deter South Korea and the United States. China was thus willing to incur more risk to neutralize North Korea from a pro-Soviet position. This article tests the theory by process tracing events in the China–North Korea–Soviet Union triangle from 1948 to 1961 with a plausibility probe of the China–North Vietnam–Soviet Union triangle from 1954 to 1965. The article concludes with implications for the contemporary China–North Korea–Russia bloc and the study of alliance politics in the Asian context.

Introduction

On July 11, 1961, China and the Democratic People’s Republic of Korea (North Korea) signed the Treaty of Friendship, Cooperation, and Mutual Assistance, formally establishing the relationship as a military alliance more than a decade after China became involved in the Korean War in October 1950 (Marxist 1961b). The timing of the treaty, however, begs a big question. Looking back to 1961, the China–North Korea treaty was redundant to deter the United States and South Korea. First, China had firmly established its credibility and resolve with respect to North Korea during the Korean War in the absence of such a treaty. There has always been little doubt about China’s intervention on North Korea’s side if a second Korean War breaks out because China shares a long land border with North Korea and it has repeatedly voiced its security assurance. Second, the Soviet Union was already a security guarantor of both China and North Korea before 1961. Throughout the 1950s the Kremlin affirmed that Soviet troops in the Far East would protect North Korea against any aggression, and it had already signed an alliance treaty with China in 1950 (Szalontai 2005, 142). Why did China agree to a treaty with North Korea when doing so would not substantially strengthen deterrence but would increase the risk of entrapment? If the rationale was to increase the overall strength of the China–North Korea alliance vis-à-vis a hostile US–South Korea alliance, why didn’t it sign one before the Korean War? Why did China have to wait until 1961?

Scholars have offered answers to these questions, ranging from deterrence against the United States, North Korea’s Premier Kim Il-sung’s adroit diplomacy against the Soviet Union and China, and China–North Korea ideological solidarity (Hoshino and Hiraiwa 2020, 19–20; Cheng 2010, 181–83; Chung and Choi 2013, 243–64; Wang and Wang 2022, 98–100). However, little work has been done to theorize the origin of the alliance treaty between China and North Korea from a triangular alliance politics perspective, especially the impact of the Sino-Soviet Split on China’s decision to sign the treaty with North Korea (Shen and Xia 2018, 138–48; Christensen 2011, 146–80; Lee 2011). Such a lack of theorizing is unfortunate considering that the China–North Korea treaty is still in effect as of 2025. Decoding the 1961 China–North Korea treaty is also important to understanding the impact of the Sino-Soviet Split on the formation of other communist alliance treaties, such as the 1965 Soviet Union–North Vietnam defense pact, besides the China–North Korea treaty (Pike 1987, 78). It is also important to comprehend the nature of the contemporary China–Russia–North Korea military bloc and the origin of bilateralism in Asian communist alliances.

This article argues that China’s decision to sign the treaty fits what alliance politics scholars call “wedge strategies,” which are policies to “prevent, break up, or weaken a threatening or blocking alliance at an acceptable cost” (Crawford 2011, 156). China signed the treaty with one major aim—to win North Korea over to its side and neutralize North Korea from a pro-Soviet position, at a time when Beijing and Moscow were having major disagreements over foreign and domestic policies. The signing of the China–North Korea alliance treaty was a part of China’s larger scheme to balance against the Soviet influence in North Korea, especially the Soviet Union–North Korea alliance treaty signed on July 6, 1961. Had China and the Soviet Union remained on good terms in the late 1950s and early 1960s, a separate China–North Korea alliance treaty would not have been necessary, since China repeatedly assured North Korea and the Soviet Union that it would fight along with North Korea to defend Korean and Chinese interests (Wilson Center 1958b). Or China could have joined the Soviet Union and North Korea as a member of a multilateral alliance like the Warsaw Pact (Wilson Center 1958a; Shen and Li 2011, 148–55). Before disagreements with the Soviet Union arose, China did not agree to sign a treaty with North Korea in 1950 because it did not have any intention of neutralizing North Korea, and entrapment risk outweighed the benefit of a more cohesive China–North Korea alliance (Snyder 1984, 467). In the end, China’s attempt to peel North Korea away from the Soviet Union succeeded in turning North Korea neutral in the Sino-Soviet Split from a pro-Soviet position several years earlier.

The article proceeds as follows. It begins with a brief overview of the cost and benefit of an alliance treaty. Next, it introduces a triangular theory of alliance formation. In the case study on the origin of the China–North Korea alliance treaty, it details how major shifts in China–Soviet Union–North Korea triangular relations affected Chinese leaders’ opinions on an alliance treaty with North Korea, especially how the motives to neutralize North Korea changed their minds from rejecting to proposing such a treaty. The article then concludes with a plausibility probe for the China–North Vietnam–Soviet Union triangle to show the external validity of the argument. The article also draws policy implications for the current China–North Korea alliance treaty in the context of the China–North Korea–Russia military bloc and for the study of alliance politics in the Asian context.

The cost and benefit of an alliance treaty

States typically sign alliance treaties to aggregate their allies’ military capability against a threat. A security commitment that is underpinned by a written document is generally stronger than one that is not (Leeds et al. 2002). A treaty signals resolve to the adversaries, generates international and domestic audience costs if one party does not fulfill its obligations, or clarifies the conditions under which a military intervention will be activated to deter the adversaries from undertaking actions that would trigger the intervention (Snyder 1990; Morrow 2000; Henry 2020; Tomz and Weeks 2021). There are, however, associated costs with such a treaty. Allies can engage in risky behaviors knowing that they can count on external assistance if the adversary retaliates, a phenomenon commonly known as entrapment (Snyder 1984; Mandelbaum 1988). States will also have to continuously reassure their allies of the treaty validity, which can incentivize free-riding and hurt their short-term bargaining leverage (Blankenship 2020).

To minimize the risk of entrapment while still courting the benefit of an aggregated military capability, states will insert escape clauses into the treaty that will absolve them of intervention responsibility if the ally initiates the conflict or undertakes risky behaviors without prior consultation (Kim 2011). In some cases, the motivation to restrain allies is even stronger than to deter enemies which incentivizes states to sign treaties to avoid being entrapped by an ill-defined expectation of support (Snyder 1997, 188–89; Pressman 2008; Cha 2016). They will also bind the risk-acceptant ally to a multilateral alliance to dilute its leverage (Narang and LeVeck 2019). A treaty by itself does not raise entrapment risk, but states must design guardrails limiting their commitment to only those areas vital to their own security (Kim 2011).

However, dissecting the cost and benefit of a treaty only makes China’s decision to sign one with North Korea more puzzling. China did not need to convince the United States and South Korea of its resolve to rescue North Korea if they marched north again after 1950. The stationing of the Chinese People’s Volunteer Army (CPVA) in North Korea during and after the war deterred and defended against the United States and South Korea. Until January 1957, China and the Soviet Union agreed that continued Chinese military presence in North Korea was important to North Korean security (Shen and Li 2011, 215). After the CPVA withdrew in 1958, China continued reassuring North Korea of its commitment. US officials in charge of Korean affairs saw that the CPVA withdrawal from Korea did not change the military balance in the peninsula, and South Korea remained vulnerable to a communist attack and subversion (FRUS 1994a; FRUS 1994b; FRUS 1994c). China had generated significant international and domestic costs for its non-treaty support for North Korea by continuously linking the importance of the Chinese revolution to the North Korean revolution and by assuming the role as the guarantor of the Asian revolution before and after the Korean War, which raised the costs of a Chinese non-intervention in the event of a resumption of the Korean War (Chen 1994). China had boasted an aggregated military capability without a treaty with North Korea.

Mao understood the entrapment risk of a treaty. Before the Korean War, Kim proposed with Mao that the two states should sign an alliance treaty (Shen and Li 2011, 216). Mao, however, wanted to sign it only after Korean unification and consultation with Moscow (Wilson Center 1950b; Wilson Center 1950c). Mao’s reluctance to sign the alliance treaty was due to his concern with being entrapped into a war that Kim started while Mao was still preoccupied with Taiwan and Tibet (Shen and Xia 2018, 27–28). However, the China–North Korea treaty did not contain any explicit escape clauses. Article II suggests that the treaty applies “in the event of one of the Contracting Parties being subjected to the armed attack by any state or several states jointly.” Article II is a weak escape clause, since it leaves open the possibility of a Chinese intervention if the United States and South Korea retaliate against a North Korean first strike, and it did not clearly define the territory under North Korean legal administrative control. This is what happened in 1950, when Beijing contemplated an intervention at the provocation of the Incheon landing, despite the fact that China had tried to escape entrapment risk to focus on Taiwan by not signing the treaty (Chen 1994, 148–54). After 1950, China’s security commitment to North Korea was not ill-defined, and clarifying it under a treaty was thus unnecessary. Importantly, had China wanted to restrain North Korea, China would have incorporated it into a trilateral alliance with the Soviet Union, considering that Beijing already had a bilateral treaty with Moscow and Moscow was about to sign one with Pyongyang (Lee 2011). Mao also could have kept the CPVA on North Korean soil or sought control of the North Korean army under a combined military command to restrain Kim. China intentionally accepted the higher entrapment risk associated with a treaty, although it had enjoyed the deterrence benefit of an alliance without a treaty and it could have minimized entrapment by leveraging its military and economic advantage for a deal with explicit escape clauses.

A triangular theory of alliance formation

What explains the origin of the China–North Korea alliance treaty? This is where the article turns next. It proposes a triangular theory of alliance formation and argues that an alliance treaty serves as a way for a state (A) to increase its influence over another state (C) at the expense of its principal competitor’s (B) influence over the said ally, even in the absence of an increase in the external threat (D) against such an alliance. A state’s act of signing an alliance treaty reflects other motivations beyond the standard capability aggregation model of alliance formation. Per the strategic triangle logic, a state signing a treaty is a result of a shift in the triangular relationship (Dittmer 1981). Under a positive-sum strategic triangle, A, B, and C are all on good terms. A and B can provide security to C against a common external D threat and minimize entrapment risk by not committing to a treaty alliance because they do not have to bid for C’s loyalty out of their own rivalry. However, the shift from a positive-sum to a zero-sum strategic triangle due to one actor’s change in behavior makes A and B view one another’s assistance to C as a threat to their respective interest, and they will seek to outbid one another to win C’s favor. If C wants an alliance treaty, A and B will meet C’s demand. A and B will even refrain from inserting escape clauses in the treaties. Such a “tug of war” results in C having more security than it needs to deter and defend against D, and A–C and B–C treaty alliances create more entrapment risk for both A and B without significantly stronger deterrence against D. This is not to say that defense against D is not important, but it is not the primary motive.

How does a state affect another state’s cost-benefit calculations in a strategic triangle (Dittmer 1981; Jervis 1997)? Both A and B employ wedge or binding strategies in a tug-of-war over C. Wedge strategies denote a state’s attempts to “prevent, break up, or weaken” an opposing alliance at an acceptable cost (Crawford 2011, 156). On the contrary, binding strategies are “policies to maintain or enhance allies’ loyalty,” which are often used to counter the wedge strategies, either in response to or in anticipation of their use (Izumikawa 2018, 109–10; Yin 2022). Under wedge strategies, a state can use selective accommodation or coercion to weaken the security partnership of the target with that state’s rival. Selective accommodation is the use of reward to induce an alignment change, while coercion involves the use of threat or sanctions for the same purpose (Crawford 2011). In response to wedge strategies, that state’s rival can either use reward binding and coercive binding (Izumikawa 2013). Reward binding denotes the use or promise of positive sanctions such as political, military, and economic support to win loyalty. On the other hand, coercive binding is the use or threat of use of negative sanctions, such as withdrawal of aid or imposition of punishment, to alter the target’s cost-benefit analysis regarding defection (Crawford 2011; Izumikawa 2018).

This is where the upgrade from an informal alliance to a treaty alliance matters. The act of signing a treaty, regardless of what is agreed upon, constitutes entanglement or a general expectation of support (Snyder 1990, 105; Snyder 1996, 174; Kim 2011). Whether states can insert escape clauses in the treaty to limit entrapment risk within that entanglement depends on their bargaining power (Kim 2011). However, they may not insert those guardrails to limit their entrapment risk out of competition with their rivals. Tongfi Kim (2011) argued that although “entrapment should never be desirable in any form,” a state may desire entanglement to benefit “from improved relationships with its ally.” An alliance treaty is not only to aggregate capabilities to deter an adversary but also to increase or maintain influence with the goal of at least neutralizing and at most realigning a potential target in one’s favor because the treaty itself is a reward (Crawford 2008). A upgrading an already credible and capable security relationship with C does not strengthen deterrence but increases A’s entrapment risk. However, such an upgrade makes sense if it allows A to maintain or increase influence over C and deny other powers such as B from doing so (Izumikawa 2018). To put it in an A–B–C triangular language, although A is already on good terms with C, the deterioration of A’s relationship with B may force A to upgrade the A–C alignment into a treaty alliance beyond what A deems necessary for C’s security even though the D threat has not increased. This is to allow A to counter B’s efforts to bind C at A’s expense.

Thanks to the zero-sum A–B competition in the strategic triangle, C can reap the benefits of the bad A–B relationship while minimizing what A and B can demand from C by leveraging its pivotal position (Crawford 2003). In the tradeoff between autonomy and security in an alliance, C can maximize its security via alliance treaties with both A and B, while preventing both A and B from requesting major concessions in exchange thanks to C’s threat of exiting either alliance (Morrow 1991). A and B will have to offer C beyond what they deem necessary to C’s needs, such as not inserting escape clauses, not only because of C’s demand but also because they do not want to lose C to the rival. Still, C’s leverage to play A off against B relies on an existing enmity between A and B, not C’s internal military and economic strength. If A and B can improve relations, C will lose its leverage and pivotal position. In short, A and B do not have to always give in to C’s demands, and C’s choices are largely shaped by A and B’s larger strategic calculations derived from the strategic triangle.

In the case study and the plausibility probe, this article wants to show three key points. First, A changing its behaviors and policies toward B causes a shift in the A–B–C triangle. Second, A perceives the motive to maintain influence over C in a new triangular pattern to be more important than the motive to cooperate with B to deter an external enemy D, which A, B, and C are originally aligned against. A is willing to make valuable concessions to C that it otherwise would not have made in the absence of a systemic shift to get C’s loyalty and to deny or decrease B’s influence over C. Third, A’s concessions have a noticeable effect on the behaviors of its target C in line with that A had planned ex-ante, which is to decrease the cohesion of the B–C relationship. Throughout the case, the paper holds the D threat constant to better test the A–B–C triangular configuration. The paper acknowledges that D’s changing level of threat to the A–B–C triangular configuration could change the triangular dynamics as well, but D’s threat alone does not explain every change to the triangular configuration, especially when the threat does not change but the triangular configuration changes.

The Sino-Soviet Split and the origin of the China–North Korea alliance treaty

The article argues that the origin of the treaty is due to China’s wedge strategies in response to and in anticipation of Soviet binding strategies towards North Korea. China originally rejected North Korea’s request for a treaty before the Korean War, but it reversed course due to the Sino-Soviet Split.

China–North Korea–Soviet Union positive-sum strategic triangle

From 1948 to 1956, China, the Soviet Union, and North Korea were in a positive-sum strategic triangle relationship. During Mao’s visit to Moscow in 1950 to sign the Sino-Soviet Treaty of Friendship, Alliance, and Mutual Assistance, the Soviet Union and China agreed that Moscow would play the role of a senior ally and a leader of the international communist movement (Low 1976, 56). After Soviet leader Joseph Stalin accepted North Korea’s invasion of the South and China entered the Korean War in 1950, the Soviet Union entrusted Beijing with the leadership of the Asian communist revolution against US-backed regimes (Wilson Center 1950a; Shen and Xia 2014). However, Stalin kept a firm control of North Korea in contrast to other Asian communist states (Shen and Xia 2014). The Soviet Union enjoyed much influence in North Korea due to its installation of the North Korean communist regime after World War II and the participation of many Soviet-Korean officials in the government (CIA 1953). From 1945 to 1950, the US State Department saw North Korea as a firm Soviet satellite as the North Korean leadership accepted the Soviet Union as the only leader of the communist bloc and granted the Soviets a monopoly over North Korea’s foreign policy to the exclusion of other influences that the Soviets deemed against their interests (DoS 1961, 103–20).

The Soviet Union and China gave credible security guarantees to Pyongyang without formal treaties. There was a clear power hierarchy in North Korea that all three powers understood, and they acted accordingly. When Stalin said no to a China–North Korea alliance treaty in May 1950, Beijing and Pyongyang did not sign one (Wilson Center 1950b; Wilson Center 1950c). It’s worth noting that Mao also did not sign a treaty with North Korea to avoid entrapment risk (Shen and Xia 2018, 27–28). During and after the Korean War, the CPVA presence strengthened Chinese influence in North Korea, but China deferred to the Soviet Union when making decisions regarding North Korea (Shen and Xia 2018). After Stalin’s death in 1953, Moscow respected China’s influence in North Korea and advised Pyongyang to heed Beijing’s recommendations (Shen and Xia 2014). Both sides worked closely to rebuild North Korea without much friction, and the Soviets did not object to China signing a ten-year economic and culture pact with North Korea in 1953 (CIA 1954). The pact would allow China to give more aid to North Korea than the Soviet Union and cancel North Korea’s war debts to China. The Soviet Union and China cooperated during the August Incident of 1956 to force Kim to stop his purges against the Moscow and the Yanan factions (Radchenko 2017). There were no wedge strategies or binding strategies employed by China and the Soviet Union against one another to attain more clout in North Korea simply because the three countries were on good terms with each other, and they respected the existing power hierarchy.

However, as Sino-Soviet relations significantly worsened starting late 1956 and 1957, shifting from a positive-sum to a zero-sum triangular relationship, they began to view one another’s influence in North Korea in a competitive light. China tried to drive a wedge into the Soviet Union–North Korea security relationship by competing with the Soviets over how much it could reward North Korea. Moscow saw China’s influence in North Korea as against its interest and thus was prepared to bind North Korea at China’s expense. The Sino-Soviet competition to win North Korea’s loyalty ultimately resulted in two different alliance treaties in 1961 signed mere days apart.

China shifting the triangular relationship

China’s disagreements with and challenge against the Soviet Union shifted the China–North Korea–Soviet Union triangle from a positive-sum to a zero-sum triangle. China was the principal driver of the triangular shift, as it increasingly became dissatisfied with Soviet foreign and domestic policies and fearful of Soviet encroachments on Chinese interest, which upended the pre-1956 status quo (Zagoria 1962). After the 1956 Polish and Hungarian uprisings, in an internal report to the Chinese Communist Party (CCP), Chinese Premier Zhou Enlai gave a negative assessment of the Communist Party of the Soviet Union (CPSU). Zhou saw that Moscow “often set the interests of the Soviet Communist Party ahead of their brotherly parties” and the CPSU would not shy from using threats and physical interferences to handle affairs within and among socialist states (Wilson Center 1957c). Zhou’s criticisms of the CPSU reflected the CCP’s emphasis on equality among states under the “Five Principles of Peaceful Coexistence” adopted in 1954.

At the 1957 Moscow Conference, China saw itself as the co-leader of the international communist movement, a status that the Soviet Union would dispute (Shen and Li 2011, 157). Between 1957 and 1958, Mao disagreed with Khrushchev in three major areas concerning China’s both international and domestic affairs: (1) Khrushchev’s “peaceful coexistence” and de-Stalinization, (2) Soviet proposal for a joint fleet and a nuclear test ban, and (3) China’s Great Leap Forward (Wilson Center 1957b; Wilson Center 1958a; Wilson Center 1958c; Wilson Center 1958d; Zagoria 1962; Luthi 2008; Shen and Li 2011; Shen and Xia 2018; Radchenko 2024). China would now strive to win North Korea’s favor by making major concessions to prevent the Soviet Union from turning North Korea against it.

China’s wedge motives behind reconciliating with North Korea

As the triangular relationship shifted beginning in 1957, Sino-Soviet cooperation in North Korea turned into a zero-sum game. China improved ties with North Korea to prevent the Soviet Union from exploiting disagreements in China–North Korea relations to turn North Korea against China. China was willing to concede to North Korea in major issues and reverse its policies to achieve its wedging objective. Three major issues in China–North Korea relations from 1956 to 1958 that saw China do a major about-face to please North Korea: China’s intervention in the August Incident, China’s support for anti-Kim Korean Workers’ Party (KWP) cadres on its soil, and China’s stationing of CPVA troops in North Korea (Shen and Xia 2018). It also sought to settle border disputes with North Korea after the 1959 Sino-Indian border clash to prevent a similar crisis on its northeastern border. These concessions would slowly build up into China’s offer of an alliance treaty to North Korea in 1960, a reward that Beijing denied in 1950 for fear of entrapment, to outbid the Soviets.

In contrast to the criticism of Kim Il-sung and the close collaboration between the Soviet Union and China in August 1956, Mao met with the North Korean delegation and apologized for the intervention at the Moscow Conference in November 1957 (Wilson Center 1956; Lankov 2002, 106–7). The apology was due to China’s intention to contest the Soviet Union’s influence over North Korea (Shen and Li 2011, 157). Mao’s apology would constitute a great power acquiescing to Kim’s domestic program and an effort to win North Korea to its side of the growing Split (Lankov 2002).

After issuing the apology, Mao saw no need to continue supporting anti-Kim KWP defectors as he did after August 1956 and promised to stop the interference (Wilson Center 1957a). Responding to these defectors’ criticism of Kim’s purge in early 1958, Zhou said “although he is not an ideal leader, he was chosen to be the ‘general’. If we do not trust him, it will be detrimental to Sino-North Korean friendship and it will also have a negative effect on Sino-Soviet friendship and solidarity” (quoted from Shen and Xia 2018, 123). China later stripped these defectors of their privilege, did not allow them to apply for CCP membership and Chinese citizenship, and prevented them from participating in matters related to China–North Korea relations (Shen and Xia 2018, 124–25). China’s hands-off approach to Kim’s purge contributed to Kim’s successful construction of a one-man rule formalized at the Fourth Congress of the KWP in 1961 (Shen and Xia 2018, 126–27). The purge allowed North Korea to rid itself of Soviet influence in domestic politics, which benefited China’s plan to neutralize North Korea (Lankov 2002, 114).

The CPVA presence is the issue that China conceded the most because the CPVA helped Beijing establish its influence in North Korea. China began to withdraw some of its troops in 1954, and in 1956, 440,000 troops remained (FBIS 1955; Shen and Li 2011, 215). In January 1957, the Soviet Union agreed with China that the CPVA should stay to defend North Korea and the entire socialist camp (Shen and Xia 2018). Mao however understood that the CPVA presence hurt China–North Korea relations because of the poor relationship between Chinese troops and the local population and the perception of the CPVA as an occupying force (Shen and Li 2011). Although withdrawing the CPVA would shift the military balance on the peninsula to the US favor, Mao wanted to improve relations with Kim to get an edge in the Sino-Soviet Split. This is a point that the standard power aggregation model of alliance cannot explain. Like the case of the purge, China did not comply with Soviet earlier recommendation to stay in North Korea. Right before the 1957 Moscow Conference, Mao proposed to Kim that he would withdraw the CPVA and that could “force the Americans to withdraw their two divisions from South Korea” (Wilson Center 1957a).

However, getting the Americans to withdraw was not a principal objective since China later still brought home its troops when the United States committed to a long-term military presence (FBIS 1958a). The United States did not see the connection between the withdrawal and Sino-Soviet Split (FRUS 1994a). China was more occupied with winning North Korean favor than deterring the United States. Still, even in the absence of the CPVA, China issued a security reassurance to North Korea. In October 1958, after the full withdrawal, China’s Xinhua News released an editorial that said, “if the U.S. aggressors dare to launch another invasion against the DPRK and if the Korean people are in need of it, the Chinese people will again organize volunteers and once again cross the Yalu River to fight alongside the Korean people and deal heavier blows to the aggressors” (FBIS 1958c). Historians agree that the CPVA withdrawal significantly improved China–North Korea relations (Shen and Li 2011).

After the 1959 Sino-Indian border clash, China saw that it was being isolated by the Soviet Union because Moscow adopted neutrality in the clash (Luthi 2008, 162). To lessen its isolation and avoid a similar clash along its northern and eastern borders, Beijing decided to resolve border disputes with North Korea and Mongolia in 1959 (Luthi 2008, 181–82; Fravel 2008, 113–15). China subsequently made territorial concessions to North Korea to strengthen bilateral relations at the Soviet expense (Shen and Xia 2013).

North Korea’s behavior changes and the Sino-Soviet “tug of war”

As China increased its concessions to North Korea after 1957 in anticipation of Soviet binding strategies, Pyongyang started to endorse many Chinese policies, including China’s hostile policies toward the United States and the Great Leap Forward, and shifted from being a pro-Soviet to a more neutral state. North Korean internal documents began to acknowledge Chinese co-leadership alongside the Soviet Union. Importantly, despite the CPSU revealing to Kim in November 1960 that Mao worried Kim might betray the communist revolution to drive a wedge between China and North Korea, Kim’s tilt to China was not hampered (Wilson Center 1960a).

Before the Sino-Soviet Split, North Korea adopted many Soviet policies as a pro-Soviet state. Between 1953 and 1957, the country modeled its collectivization program after that of the Soviet Union, and Pyongyang followed the Soviet example when crafting the First Five-Year Plan (1957–1961) (Chung 1978). Pyongyang refrained from endorsing China’s attacks on Jinmen Island and its general hostility towards the United States, in line with what Moscow was doing (Chung 1978). North Korea however began to change its behaviors incrementally after Chinese concessions. A month after the withdrawal of the CPVA, Kim Il-sung visited China in November 1958, during which China and North Korea signed a trade pact that covered the 1959 to 1962 period (FBIS 1958b). Kim endorsed Mao’s statement that “US imperialism is only a paper tiger” and supported the Great Leap Forward (FBIS 1958d). Kim added that “the development of economic and cultural relations with the CPR [Chinese People’s Republic] will provide tremendous support to our country’s socialist construction undertakings” (FBIS 1958e). The China–North Korea joint statement also demanded that the United States withdraw from South Korea and from Chinese territory, effectively linking the Taiwan issue with the Korean issue. This signaled North Korea’s nod to Chinese hostile policies towards the United States (FBIS 1958f). When Kim returned to North Korea, the country officially started its own Great Leap Forward, the Chollima Movement. In 1958, North Korea began to use the phrase “the socialist camp led by the Soviet Union and China” in its internal KWP speech (Shen and Xia 2018, 126–36).

However, Kim did not want to upset the Soviet Union. In January 1959, Kim accepted Khrushchev’s criticism of Chinese economic policy, affirmed the Soviet Union as the bloc leader, and asked it for more aid, including Kim’s proposal for an alliance treaty to make up for the imbalance in force with the South after the CPVA withdrawal (Shen and Xia 2018, 145; Lee 2011). Kim’s request for an alliance treaty with Moscow forced Mao to change his mind regarding the alliance treaty with Pyongyang (Lee 2011). In March 1960, Mao communicated with his aides that he was open to signing an alliance treaty with Kim (Shen and Xia 2018, 145). Soon, China communicated the intention to North Korea (Shen and Xia 2018, 145). This marked a major policy reversal because, as he had declared in 1950, Mao did not want to sign such a treaty before Korean unification (Wilson Center 1950b; Wilson Center 1950c). The decision was not to compensate for the CPVA withdrawal in 1958, because if that had been the case, Mao could have offered a treaty then. China also made clear that the CPVA would return only when North Korea asked for it to show respect for Korean sovereignty (FBIS 1958c). Mao’s offer for an alliance treaty, including his desire to concede over border issues with North Korea, was to improve China’s security environment in the face of Soviet efforts to isolate China after 1959 (Luthi 2008, 181–82; Shen and Xia 2013). It was also remarkable that North Korea did not ask for an alliance treaty with China first, despite the fact that it was the Chinese who caused the force imbalance in the first place. This showed Kim was still leaning on the Soviet side while improving relations with Mao.

Khrushchev also did an about-face to bind North Korea. Initially Khrushchev did not want to sign a treaty with North Korea due to his prioritization of “peaceful coexistence” from late 1959 and early 1960 (Lee 2011, 94; Shen and Xia 2018, 145). In June 1960, one month before he recalled all Soviet specialists from China, Khrushchev promised to sign an alliance treaty with Kim when he visited North Korea (Shen and Xia 2018, 146). However, Khrushchev postponed his visit to North Korea and the signing of the treaty (Pearson 2012). Moscow also attempted to undermine China’s reward to North Korea by showing Kim a document saying that Mao thought Kim was a traitor to the communist revolution. Kim was furious and reassured Moscow that the KWP “always supported and does support the CPSU CC [Communist Party of the Soviet Union Central Committee] line on all of the most important issues” (Wilson Center 1960a). Still, North Korea continued receiving aid from China and signed a new loan deal with it (Wilson Center 1960b; FBIS 1960). Pyongyang leveraged its pivotal position to extract concessions with both patrons. At the November 1960 Moscow Conference, the KWP publicly recognized China as the co-leader of the bloc, using the language “the socialist countries led by the Soviet Union and the Chinese People’s Republic” instead of “the socialist countries led by the Soviet Union” (Chung 1978, 53).

Kim succeeded. When it was now clear that Moscow was losing its grip on Pyongyang, Soviet first vice chairman of the Council of Ministers Alexei Kosygin visited North Korea in May 1961. Kosygin invited Kim to come to Moscow to conclude the alliance treaty that Khrushchev had promised in June 1960 (Shen and Xia 2018, 146). Upon hearing the news, China immediately invited Kim to Beijing after his visit to the Soviet Union to conclude a China–North Korea alliance treaty (Lee 2011; Shen and Xia 2018, 146). Kim finally told China that he accepted Chinese offer for a treaty one day before he departed for Moscow on June 28 to sign the treaty with the Soviet Union (Lee 2011). During the subsequent negotiations, China asked North Korea for a draft of the Soviet–North Korean treaty, not the 1953 US–South Korea alliance treaty, as the basis to write the Chinese–North Korean treaty (Lee 2011). The Soviet Union–North Korea alliance treaty was signed on July 6, 1961, and the China–North Korea alliance treaty was signed on July 11, 1961. It took the Chinese–North Korean treaty only two weeks to materialize after Kim accepted the Chinese offer.

The two alliance treaties confirm that the Soviet Union and China accepted entrapment risk. Article I of the Soviet–North Korean treaty and Article II of the Chinese–North Korea treaty, which required Moscow and Beijing to come to Pyongyang’s defense if the latter was attacked, left open the possibility of them intervening on North Korea’s behalf if the United States and South Korea retaliated against a North Korean first strike (Marxist 1961b; UN 1961). This was the case again in 1950. Unlike the US–South Korea alliance treaty, the two treaties did not define the territory under North Korea’s administrative control to restrain Pyongyang. The United States has restrained Seoul by clearly defining South Korean administrative territory and only offers assistance to Seoul “in the event of an armed attack against territory which has been recognized by the United States as lawfully brought under the administrative control of the Republic of Korea” (USFK 1957; Cha 2016). Some might argue that, because North Korea was so important to Chinese and Soviet security, their entrapment risk was minimal, as Beijing and Moscow would have rescued North Korea anyway. However, not specifying the geographical scope of the defense pledge meant Beijing and Moscow could be entrapped into a war that North Korea started. Not only did China model the treaty after the Soviet–North Korean one but it also sought to outbid the Soviets by not putting an expiration date on the treaty. The Chinese–North Korean treaty would remain valid so long as both sides agreed to extend it; while the Soviets agreed that the treaty would be valid for only ten years and could be renewed for another five years if both parties consented. Scholars agree that the Chinese–North Korea treaty contained stronger security guarantee than the Soviet–North Korean treaty (Shen and Xia 2018, 147; Lee 2011, 101).

China succeeded in neutralizing North Korea with the treaty. In both treaties, North Korea pledged not to join any alliances or undertake any actions that would hurt the interests of its co-signatories, the Soviet Union and China. In the Sino-Korean joint communique on the treaty, Beijing and Pyongyang expressed support for their respective struggles to liberate Taiwan and South Korea (Marxist 1961a). Kim was happy with both treaties, claiming that “The Soviet Union and the Chinese People’s Republic are our two great neighbors and closet fraternal countries” (quoted in Chung 1978, 60). China praised the treaty as a joint China–North Korea struggle against US imperialism and “the main danger to the current international communist movement—the Yugoslav modern revisionism” (FBIS 1961). China only said the treaty would contribute to the unity of the socialist camp without mentioning the Soviet Union as the camp leader in either the joint communique or the media statement. The media statement was implicitly directed against the Soviet “revisionists,” and it affirmed China’s intention to neutralize the Soviet influence in North Korea.

China’s wedge strategy to neutralize North Korea did not stop the formalization of the Soviet Union–North Korea security partnership into a treaty alliance, showing the limitation of Chinese efforts. Such limitation was due to the asymmetric nature of the Soviet Union–North Korea alliance, which allowed the Soviet Union much ability to offset the Chinese reward to North Korea (Huang 2020). China’s concessions also support Kim’s (2011) argument that whether a state can insert escape clauses in an alliance treaty depends on its bargaining power. And China did not have much in this context. However, China’s efforts were enough to prevent North Korea from undertaking any actions harmful to Chinese interests as the Sino-Soviet Split worsened throughout the 1960s. Despite China–North Korea ties deteriorating during the Chinese Cultural Revolution and the Soviet Union threatening to attack China, North Korea maintained its neutrality to continue reaping rewards from both patrons (Shen and Xia 2018). Had China not committed North Korea to an alliance to buy its loyalty, a pro-Soviet North Korea with unsettled border issues with China would have been much more dangerous to China’s security along the northeastern border.

Alternative explanations

Throughout the case study, this article has been able to hold the ideology of North Korea and China constant, which challenges the argument that Beijing and Pyongyang signed the treaty because of ideological solidarity. If that was the case, Mao should not have rejected Kim’s request for such a treaty before the Korean War, considering North Korea’s support for Mao during the Chinese Civil War. China’s need for North Korea’s ideological support after the Split in 1957 explains Chinese concessions and arguably Mao’s offer for a treaty. However, the root cause of such a need was a shift in the China–North Korea–Soviet Union relationship from a positive-sum to a zero-sum triangle. Had China not contested the Soviet leadership of the international communist movement, it would not have needed North Korea’s ideological support and signed the treaty as it was the case between 1948 and 1956.

This article contests the argument that the treaty was signed to balance against the United States and South Korea. The evidence shows Mao was willing to withdraw the CPVA from North Korea in support of his competition against the Soviet Union. If the treaty was to balance against Seoul and Washington, Mao again should have agreed to one before 1961, such as in 1953 when the United States and South Korea signed a mutual defense treaty, or in 1958 after the CPVA withdrew. Again, the number of US troops in South Korea did not change during the examined period and even declined compared to during the Korean War, indicating that the US threat was not the key factor behind the decision to sign the treaty (Izumikawa 2007). The South Korean coup in May 1961 came after Mao’s proposal to sign a treaty with Kim in 1960, which also suggested the coup was not the main factor. Even Pyongyang was initially supportive of the coup because its leader Park Chung-hee was a member of South Korea’s Labor Party, and it did not expect a war to “break out today or tomorrow” (Wilson Center 1961a; Wilson Center 1961b). North Korea believed that it had the upper hand due to South Korea’s political instability and economic backwardness (Wilson Center 1961a). Pyongyang’s perception of the US–South Korean threat was not severe enough for it to accept the Chinese offer for a treaty. Kim asked for a treaty with Moscow in 1959, but he did not accept one with China until June 1961 after he had secured Khurschev’s promise to sign one.

Some may thus attribute the Chinese–North Korean treaty to Kim’s diplomatic acumen. Indeed, Kim did not let his Soviet patron know about his plan to sign a separate treaty with China as he departed for Moscow (Lee 2011, 98). Signing a treaty with the Soviet Union first, after two years of waiting for official approval, and with China later allowed Kim to not upset Moscow while forcing Beijing to offer him what Moscow had promised. While it may be true that Kim was able to exploit the Split to his favor, he did not cause the Split in the first place. When the Soviet Union and China were on good terms, Kim could not press his demands for a treaty in 1950 with China. Moscow’s hesitance to sign a treaty with Kim in 1959 after the Split had worsened also demonstrated Kim’s limited agency to exploit the Split. The article can attribute the origin of the China–North Korea treaty to China’s wedge strategies against the Soviet–North Korean partnership.

The China–North Vietnam–Soviet Union triangle: A plausibility probe

The theory travels beyond the China–North Korea–Soviet Union triangle. The China–North Vietnam–Soviet Union triangle demonstrated similar features, as the Soviet Union made a U-turn in its policy toward Vietnam to drive a wedge into the China–North Vietnam alliance (Khoo 2010). North Vietnam relied heavily on China for military and material support during the First Indochina War against France (1946–1954) because Stalin had delegated the task of supporting Asian communist revolution to Mao. Moscow and Beijing did not compete over Vietnam during this time because they were on good terms. The Soviet Union was one of the parties present at the 1954 Geneva Conference to partition Indochina, but Moscow did not want to be involved in Vietnamese affairs (Olsen 2006, 69). After Geneva, the Soviet Union rejected Hanoi’s request for military assistance because it feared that an emboldened North Vietnam might attack South Vietnam and imperil Khrushchev’s policy of peaceful coexistence (Roberts 2006, 10–11). Like North Korea before the Split, the Soviets and the Chinese cooperated to force North Vietnam to accept the partition at the seventeenth parallel and to maintain the post-Geneva status quo in Indochina without committing to a treaty alliance with Hanoi (Olsen 2006, 70). North Vietnam complied with the Soviet and Chinese demand to abide by the Geneva settlement. The China–North Vietnam–Soviet Union triangle was positive-sum. The Split would shift the China–North Vietnam–Soviet Union triangle to a zero-sum one.

China was the first country to change its policy toward North Vietnam as the Second Indochina War (1955–1975) was brewing. The United States increased military assistance to South Vietnam in late 1961 to support Saigon’s crackdown on communist activities. In response, China assured the North Vietnamese leadership that Beijing would “have to intervene as had happened in Korea” if the United States attacked North Vietnam close to the Chinese border (quoted in Yin 2019, 247). Contrarily, Khrushchev did not want to provide North Vietnam with a security assurance like China had done despite the U.S. growing footprint in South Vietnam (Gaiduk 1996, 11–14; Yin 2019, 245–46). Beginning 1964, China and North Vietnam inked several military assistance agreements on the conditions of a Chinese military intervention to defend Hanoi and on Chinese troops presence on North Vietnamese soil, which China later fulfilled by sending air defense and logistical troops to help Hanoi defend against US bombings and repair infrastructure (Zhai 2000, 133–34; Khoo 2010). Due to China’s support, North Vietnam was firmly on China’s side of the Split, evidenced by its support for China’s rejection of the 1963 Limited Test Ban Treaty and its condemnation of Yugoslav revisionism (Chen 1964, 1029–35).

The Soviet Union’s calculation vis-à-vis Vietnam only changed after Khrushchev’s departure in October 1964, when the Soviets realized how much influence China had over North Vietnam. After initial efforts to mend fences with China failed and worsened the Split, the Soviet Union, under the leadership of Leonid Brezhnev, decided to increase military support to Hanoi to drive a wedge between China and North Vietnam. To reverse Khrushchev’s passive policy toward Vietnam, Kosygin traveled to Hanoi in February 1965. The visit saw Moscow committed to Hanoi’s security via a joint statement that the CPSU Central Committee later ratified as a defense pact (Pike 1987, 78–79). ¹ The joint statement read,

abiding by the principles of socialist internationalism, the Soviet Government cannot remain indifferent to the ensuring of the security of this fraternal socialist country and will extend the necessary assistance and support to the Democratic Republic of Vietnam … the two governments have reached an appropriate agreement on the measures to be carried out with a view to consolidating the defense of the DRV.

(FBIS 1965d)

Brezhnev confirmed the existence of an agreement with Hanoi to strengthen the DRV’s defense in March (FBIS 1965a). In May, the Supreme Soviet repeated the assurance, “If the U.S. aggression against the DRV increases, the Government of the Soviet Union will, when necessary and at the request of the Government of the DRV, agree to send to Vietnam the Soviet citizens … to defend the socialist fruits of the DRV” (FBIS 1965c; FBIS 1965b). Although evoking the shared US threat, the Soviet move was primarily to counter China’s influence in Vietnam (Pike 1987, 79; Duiker 1996, 251; Christensen 2011, 181–82). The Soviets leveraged its economic and military aid to Hanoi to win Hanoi’s loyalty at Beijing’s expense (Khoo 2010).

Official Vietnamese history confirmed that from April 1965 to May 1966, more than 2200 Soviet air defense experts came to Vietnam to train its military (Nhan Dan 2025). Hanoi slowly shifted from a pro-China position to a neutral one in the Split, even rebuffing Beijing’s upset at Hanoi’s receipt of Soviet aid and its peace talks with the United States, exactly how the Soviet Union intended North Vietnam to behave (You 2023). China, to bind North Vietnam from Soviet wedges, increased its aid in response (Khoo 2010). The Soviets and Chinese also squabbled over the delivery of aid to Hanoi because Soviet aid had to pass through China via rail, which hampered Hanoi’s ability to fight the United States (CIA 1968; Radchenko 2024, 338–40).

Like North Korea, North Vietnam stayed neutral, and it leveraged the Split to extract the most amount of assistance from its two communist patrons to execute the war (Roberts 2006; You 2023). Due to the Split, Moscow and Beijing backed Hanoi’s militant unification policy toward South Vietnam, a reversal of their restraint on Hanoi in the mid-1950s. When the Sino-Soviet relations were amicable, North Vietnam could not demand military assistance from Moscow. Had the Soviet Union wanted to deter the United States from attacking North Vietnam, it would have granted Hanoi a security commitment around 1961, 1962, or 1964, like China did, and not waited until 1965 after China had committed to Hanoi’s defense. And by evoking its intervention during the Korean War, China’s security guarantee alone would have sufficed to stop a US march north in Vietnam (Roberts 2006). During the First Indochina War, China’s threat of intervention without Soviet backing deterred France from attacking the Vietnamese communists’ bases along the China–Vietnam border (Goscha 2022). Moscow in essence entangled itself in the Second Indochina War to win Hanoi’s favor. The Soviet Union did not compete against China in North Vietnam as early as it did in North Korea. As the Sino-Soviet Split worsened, the competition spread from Northeast Asia to Southeast Asia. Changes in the China–North Vietnam–Soviet Union triangular dynamics explained the Soviet decision to reverse policy toward Vietnam.

Conclusion: Evolution of the China–North Korea treaty after the Cold War

The China–North Korea alliance treaty was a product of China’s own strategic calculation under a triangular relationship with North Korea and the Soviet Union. China increasing its entrapment risk is not without long-term consequences. Although the Soviet–North Korean treaty expired in 1996, China has kept its treaty. The Soviet collapse has allowed China to scale back some of its support for Pyongyang because North Korea no longer enjoyed great leverage. China now wants to restrain North Korea’s provocations by limiting the condition under which the treaty will apply, and it deters the United States and South Korea by dangling the threat of a Chinese intervention (Wong 2020). When North Korea and the United States were in a crisis in 2017, China for the first time clarified the condition that would activate its intervention. China declared that it would not come to North Korea’s aid if it attacked the United States first and Washington retaliated, and it would only defend North Korea if Washington struck first (Washington Post 2017; Chen 2017). This condition mirrors the US restraint intention in its treaty with Seoul. With the revival of the Russia–North Korea alliance treaty in 2024 and the image of Chinese President Xi Jinping flanked by Russian President Vladimir Putin and North Korean Chairman Kim Jong-un at China’s Victory Day Parade in 2025, the China–North Korea–Russia triangle is back to being positive-sum. This suggests that neither Russia nor China will compete to win North Korea’s loyalty.

This article adds to the growing literature on how states drive wedges among adversaries by highlighting alliance treaties as a means of statecraft beyond deterrence and defense (Crawford and Vu 2021; Yin 2022; Crawford 2024; Kim and Simon 2025). It also contributes an important perspective on the nature of alliances in Asia. While scholars have pointed out that there is no NATO in Asia, few emphasize a similar phenomenon that there is also no Warsaw Pact in Asia. As the paper argued, the Sino-Soviet Split shattered any prospect of a multilateral alliance among Asian communist countries. If the United States could leverage its power to restrain Asian allies via bilateral treaties, the Split weakened both Moscow’s and Beijing’s bargaining power vis-à-vis their small allies. Bilateralism in the communist context encouraged rather than restrained small allies’ adventurism. Consequently, North Vietnam and North Korea, neither embedded in a multilateral alliance nor restrained by their patrons via bilateral treaties throughout most of the Cold War, enjoyed a greater freedom of action than what their humble military strength would have allowed. Hanoi could liberate South Vietnam and fight a war against China, while Pyongyang could pursue and obtain nuclear weapons. These are what South Korea and Taiwan wish they could have done. Indeed, they both tried but failed.