1. Introduction

From its earliest days, the Nixon administration advocated for a policy of global détente, which involved disengagement from the Vietnam War and its related issues. During President Nixon’s visit to Guam, he articulated that “as far as the problems of military defense, except for the threat of a major power involving nuclear weapons, that the U.S. is going to encourage and has a right to expect that this problem will be handled by, and responsibility for it taken by, the Asian nations themselves [1].” While there were differing interpretations of Nixon’s stance, it should be clarified that it did not signify a complete withdrawal of the U.S. Rather, it signified an intention to reduce costs and risks in the region while urging Asian allies to bolster their own self-reliance or self-help capabilities.

The reduction in U.S. military forces and nuclear deployments was accompanied by the promotion of each country’s self-reliance efforts in bilateral relations. Notwithstanding, every nation pursued its individual national interests in unique ways, striving for “self-reliance.” For instance, South Korea and Taiwan’s efforts to enhance their relations with China faced challenges, while Japan and the U.S. seemed to have counterproductive results in this regard. China’s “One-China” policy could have made it difficult for Taiwan to welcome any progress in the relationship between the U.S. and China or Japan and China, implying that it may have been challenging for Taiwan to accept any such improvements. In contrast, South Korea had the option of coordinating with Japan and the U.S. in dealing with China while maintaining hostile relations with the Democratic People’s Republic of Korea (North Korea). Uniquely, South Korea has been active in the construction of a multilateral security framework that is inclusive of non-communist countries.

In the following section, we discuss the transformation in the security landscape driven by the U.S., including the reduction of U.S. forces stationed in East Asia’s Allied countries of Japan, South Korea, and Taiwan, changes in the deployment of nuclear weapons, and the establishment of a regional framework for multilateral cooperation in Asia, influenced by South Korean initiatives in the 1960s. As we assess the regional developments from the latter part of that decade onwards, we will analyze the responses of the involved countries from diverse angles. The methods used to develop this chapter were informed by a variety of literature sources and government reports in order to provide a thorough and qualitative analysis.

2. The ongoing relationship hidden from public view

In August and September 1948, two separate governments were established on the Korean Peninsula. By December 1949, Chiang Kai-shek’s government had relocated the capital of the Republic of China to Taipei. This event marked the beginning of the Cold War confrontation with East Asia; It is noteworthy, however, that no U.S. combat troops were stationed in Taiwan at the time. When the Korean War broke out, Taiwan expressed its desire to participate but ultimately opted not to intervene directly. During the war, the U.S. deployed the Seventh Fleet to the Taiwan Strait, to prevent further escalation of the conflict, and utilized the region for logistical support. Taiwan played a supportive role by assisting UN forces and accommodating some Chinese prisoners of war due to Chinese involvement in the conflict. In addition, “the U.S. established a defense command in Taipei and sent a Military Assistance Advisory Group (MAAG) to Taiwan under the command of a two-star general [2].” For a period following this, U.S. forces remained stationed in Taiwan, albeit with a limited number of troops.

According to the Global U.S. Troop Deployment, 1950–2005 by Tim Kane,

America positioned thousands of troops in Hong Kong and Taiwan, starting abruptly in 1954. At their peak in 1957, there were 4539 American soldiers in Hong Kong, which were quickly drawn down to levels of 290 and then 26 over the next 2 years. The situation was similar in Taiwan, with a sudden buildup from 811 to 4174 troops in 1954, with levels peaking in 1958 at 19,000 and then stabilizing between 4000 and 10,000 until 1977 [3].

When compared to the 1954 Taiwan Strait Crisis, it becomes apparent that a larger number of U.S. troops were deployed during the 1958 crisis. However, following the resolution of the crisis, the number of U.S. troops stationed in Taiwan decreased. This trend extends beyond Taiwan and aligns with the overall decrease in the number of U.S. troops deployed overseas.

The number of U.S. troops stationed overseas witnessed fluctuations, notably with a surge during a large-scale U.S. involvement in the Vietnam War, followed by a reduction due to policy shifts by the Nixon administration. Based on data from David Coleman’s “U.S. Military Personnel 1954–2014,” also depicted in Figure 1, the highest number of U.S. troops was recorded in 1968 at 3,547,902. However, this number began to decline when the Nixon administration implemented an exit strategy during the Vietnam War. The number of U.S. troops decreased to 2,081,910, with the most significant personnel reduction occurring in the Army, which decreased from 1,570,343 in 1968 to 779,417 in 1976 during the Nixon administration. During the same period, the Navy decreased from 765,457 to 524,678, the Marine Corps decreased from 307,252 to 192,399, and the Air Force decreased from 904,850 to 585,416. These changes occurred at the end of the Vietnam War and continued after [4].

Figure 1.
U.S. military personnel 1954–2014.

In January 1979, the U.S. formally recognized the People’s Republic of China as the legitimate government and terminated official diplomatic relations with Taiwan [5]. This decision has had significant implications for U.S.-Taiwan military ties. The United States Taiwan Defense Command (USTDC) “formally lowered its flag on April 26, 1979. One year after the break in diplomatic relations, the Carter administration terminated the U.S.-ROC Mutual Defense Treaty” [6]. Maintenance of unofficial relations with Taiwan and the U.S. was ensured when Congress passed the Taiwan Relations Act of 1979. The act emphasized the U.S. commitment to assist Taiwan in maintaining its self-defense capabilities, which became a cornerstone of U.S.-Taiwan relations. As part of this commitment, arms were provided [7]. It is worthy of consideration, that the U.S. maintains unofficial relations with Taiwan, and there is no permanent U.S. military presence on the island [8]. Therefore, “all American forces were pulled out in 1979, in a withdrawal that clearly began in 1973, after President Richard Nixon’s diplomatic opening with the People’s Republic of China” [3]. U.S. policy toward Taiwan has evolved over the years, reflecting changes in the geopolitical landscape and the dynamics of U.S.-China relations.

With reference to nuclear weapons in Taiwan, the U.S. government announced that nuclear weapons could be used during the first Taiwan Strait Crisis in early March 1955 [9]. However, “the Eisenhower administration considered many options, ranging from convincing Chiang Kai-shek to giving up the Islands to employing nuclear weapons against the PRC. To ease tensions, concern about [sic] the very real possibility of war with the U.S., or changes in internal politics” [10]. The decision to use nuclear weapons is complex and influenced by various factors, including the global geopolitical situation and the potential consequences of nuclear escalation. The U.S. likely refrained from using nuclear weapons to avoid conflict with China and the Soviet Union and to prevent nuclear war. Diplomacy and conventional military measures were prioritized, to deal with the situation, without resorting to nuclear escalation.

During the Second Taiwan Strait Crisis, when Kinmen (also known as Quemoy) was under attack by China, the U.S. explored the option of utilizing nuclear weapons. Richard D. Fisher, Jr. writes, “in response to the 1958 Taiwan Strait crisis, which included massive Chinese artillery shelling and aerial combat, the U.S. Air Force briefly deployed 20 kiloton nuclear warhead armed with MGM-1 Matador cruise missiles to Taiwan” [11]. However, the decision not to use nuclear weapons during the second crisis was influenced by several factors. The mutual assured destruction in the Cold War context, between the U.S. and the Soviet Union, as the two superpowers, instilled caution in both sides when it came to provoking a nuclear conflict. The use of nuclear weapons had the potential to escalate tensions and result in widespread, catastrophic wars. The U.S. responded to the crisis using diplomatic efforts and conventional military means, avoiding the use of nuclear weapons, to maintain stability and prevent a more extensive global conflict.

There is currently no widely accepted evidence to support the claim that the U.S. deployed a nuclear arsenal in Taiwan. However, as per Hans Kristensen’s study, it has been suggested that nuclear bombs were present in the region from January 1960 until July 1974 [12]. Contrastingly, Taiwan made serious efforts to develop its own nuclear weapons, mainly due to China’s nuclear test in October 1964. In a recent study, it was found that “around 1966, President Chiang directed Taiwan’s Chungshan Science Research Institute (or Chungshan Institute), under the Ministry of Defense, to draw up a specific plan for nuclear weapons development, which was titled “Plan Hsin Chu” or “Hsinchu Project” [13].

With reference to Taiwan’s nuclear weapons project, in 1974, the “CIA concluded that Taiwan was working toward a nuclear weapon capability and would be capable of producing a nuclear weapon within 5 years” [14]. The nation signed the Non-Proliferation of Nuclear Weapons (NPT) in July 1968, which was ratified by the government 2 years later [15]. In January 1979, with the normalization of diplomatic relations between the U.S. and China, all military presence in Taiwan, including nuclear weapons, was withdrawn. Taiwan’s “self-reliance” efforts may have also grown, especially regarding the nuclear project [16]. However, “there is no evidence that Taiwan has pursued a nuclear weapons capability since the U.S. shut down its program in 1988 (or even thought about pursuing one);” [17] according to a recent study, Taiwan cooperated with the U.S. for denuclearization in 1998. Additionally, “a U.S. team of specialists arrived in Taipei to implement and verify the denuclearization” in 1988. Work was well underway toward denuclearization, and Taiwan finally decided to dismantle its nuclear weapons program as “irreversible” [13]. The usefulness of the U.S. nuclear umbrella, however, remains unclear. Taiwan’s future security is closely tied to the trajectory of U.S.-China relations. Additionally, as of 2023, there have been reports of approximately 200 U.S. military advisors present in Taiwan, although the government has not officially confirmed this information [18].

Prior to Taiwan’s efforts toward complete denuclearization, a significant exchange occurred between the U.S. and the Soviet Union. The Reykjavik Summit was held on October 11–12, 1986, when US President Ronald Reagan and Soviet Communist Party General Secretary Mikhail Gorbachev met in Reykjavik, Iceland. The U.S. intended to discuss human rights and the Soviet invasion of Afghanistan during the talks, while the Soviet Union primarily focused on arms control. Unfortunately, the conversation broke down at the last minute. Although the Reykjavik meeting did not achieve its ultimate goal, it retained its place among the most significant historical events. Following the meeting, the U.S. and the Soviet Union signed crucial agreements that marked the end of the Cold War. The first was the Intermediate-Range Nuclear Forces Treaty (INF), which mandated the liquidation of all nuclear weapons by both sides 1 year after the Reykjavik talks. The Strategic Arms Reduction Treaty (START), signed during the presidency of H.W. Bush, prohibited the deployment of 6000 nuclear warheads, 1600 intercontinental ballistic missiles, and bombers [19]. Cooperation in nuclear disarmament between the U.S. and the Soviet Union had a significant impact on the situation on the Korean Peninsula, as will be discussed later.

3. United States primary alliances

The history of U.S. military presence in Japan is both lengthy and complex, primarily because of the aftermath of World War II and the U.S. occupation and security regime in Japan. General Douglas MacArthur served as the Supreme Commander for the Allied Powers (SCAP), also known as the General Headquarters (GHQ) in Japan and played a crucial role in shaping postwar Japan [20]. By the end of 1945, approximately 430,000 American soldiers were stationed throughout the country [21]. As the Cold War confrontation in East Asia took shape, there was a shift in U.S. policy toward Japan. In September 1951, with the exception of a few countries, the allies signed the Treaty of Peace with Japan, which officially ended Allied occupation and restored Japan’s sovereignty. According to data from the Japan Defense Agency (JDA) in 1982, approximately 26,000 U.S. troops were present in Japan during the post-war occupation by the GHQ when the treaty took effect in April 1952 [22]. In 2007, the JDA was officially changed to the Ministry of Defense. In addition, the Korean War resulted in the establishment of the Police Reserve Corps, in August 1950, which later became the Self-Defense Force in July 1954.

Throughout the Cold War, Japan played a pivotal role in the U.S. defense strategy within the Asia-Pacific region. The U.S. military maintained a significant presence in Japan, encompassing its bases and facilities, as part of its commitment to regional security. In particular, U.S. troops were stationed in Okinawa, which remained occupied despite the peace treaty and served as a significant hub for U.S. military personnel and bases. The presence of the U.S. military in Okinawa has been a source of tension in U.S.-Japan relations. This has resulted in various agreements and negotiations over the years, to address the concerns of the local population. During negotiations regarding the Okinawa reversion, the Nixon administration accomplished its primary objective of reaching an agreement on the future status of Okinawa. This alleviated the concerns of both the Joint Chiefs of Staff, who were apprehensive about Okinawa returning to Japanese control. It is important to consider the potential cost of the U.S. capacity to fulfill its political and military commitments in East Asia, as well as the concerns of the Japanese public. The Japanese people hold strong sentiments against militarization, nuclear weapons, and the U.S. presence, and it is crucial to acknowledge and address these concerns. As expected, the primary documentation of Okinawa’s reversion to the U.S. was produced by government departments specializing in national security and foreign policy. Simultaneously with the ongoing negotiations, in 1969, the U.S. military presence in Japan was primarily composed of marines, comprising roughly half of the total U.S. military presence [22].

As the Nixon administration changed its foreign policy and actively promoted it, the number of troops stationed in the country dropped to approximately 26,500 in 1971, marking its lowest level historically. Among the East Asian Alliance countries, Japan has consistently hosted the largest number of U.S. troops for many decades. As of 2019, there were approximately 56,100 U.S. forces stationed in Japan, including approximately 20,500 marines [23]. U.S. troops continue to be stationed in Japan as part of the U.S.-Japan security alliance. The number and distribution of U.S. troops in Japan may be subject to adjustments and negotiations between the two countries.

The atomic bombing of Hiroshima and Nagasaki in August 1945 has been a significant event in US-Japan relations. In 1948, during the escalation of the U.S.-Soviet conflict, the U.S. provided Britain with a weapons system that was capable of carrying nuclear weapons. This marked the first time the U.S. deployed a nuclear weapons system outside the country [24]. Shortly after the onset of the Korean War, on July 1, 1950, the Truman administration decided to deploy non-nuclear components to Guam, with the potential capability to incorporate nuclear warheads [25]. In 1954, the U.S. deployed its first nuclear weapons in Japan, although this was never officially confirmed or documented. The Federation of America Scientists (FAS) report states that between 1954 and 1972, Okinawa hosted 19 different types of nuclear weapons, with the bulk of them stored at the Henoko Ordnance Ammunition Depot adjacent to Camp Schwab and the Kadena Ammunition Storage Area From 1954 to 1972 [26]. During the Cold War, the U.S. extended its nuclear umbrella to its allies, including Japan, to deter potential adversaries in the Asia-Pacific region, notably the Soviet Union and China [27]. The U.S. implemented a “nuclear sharing” arrangement that involved placing American nuclear weapons at various bases in Japan, including Okinawa and mainland Japan. These weapons were intended for use by the U.S. and Allied forces in the event of a conflict, or to deter nuclear war. The details of the number and types of nuclear weapons, as well as their specific locations in Japan, were kept secret, and the U.S. maintained a policy of neither confirming nor denying the presence of such weapons [28].

In the late 1960s, as mentioned above, Taiwan, stimulated by China’s nuclear test, began to develop its own nuclear weapons. Japan also began the development of nuclear weapons when it was certain that there would be a regime change in the U.S. Green and Furukawa reported that, between the late 1960s and the early 1970s, two groups studied the possibility of Japan becoming a nuclear weapons state [14]. Furthermore, as the Nixon administration’s détente policy progressed, the number of U.S. nuclear weapons within its East Asian allies’ territories also saw a significant reduction. As shown in Figure 2, “By 1977, it had fallen to about 1200 warheads. Politically charged warheads were withdrawn from Japan, and the Philippines was denuclearized virtually in secret. The Strategic Air Command (SAC) reduced its presence in the Pacific, and U.S. warheads were withdrawn from Okinawa soon after reverting to Japan in 1972. By the end of the 1970s, only South Korea remained as a forward base for U.S. nuclear weapons” [25].

The issue of U.S. nuclear weapons in Japan has been a topic of public alarm and has led to protests due to concerns about safety and environmental implications. It is worth noting that the details and scope of these deployments have been the subject of historical research and declassification efforts. “At the height of the Vietnam War, approximately 1200 nuclear weapons were stored in Okinawa alone. A document published in 2017 shows that, in 1969, Japan officially consented to the U.S. bringing nuclear weapons to Okinawa” [26]. However, in 1993, Kei Wakaizumi published a book uncovering the truth behind the 1969 secret agreement, which ensured Okinawa’s return to Japanese jurisdiction in 1972. It was revealed that U.S. nuclear weapons could have been brought to Okinawa without being deployed [29]. The presence of nuclear weapons in Japan was not a permanent condition; rather, it was influenced by geopolitical factors and shifting U.S. defense policies.

4. Responding actively to “self-reliance” (partially due to geopolitical background)

The decrease in U.S. troops stationed overseas has been especially noticeable in South Korea. The presence of U.S. troops in South Korea has fluctuated since the end of the Korean War, which has had a significant impact on the country. According to the report by Tim Kane, “Only 510 servicemen were based in South Korea in 1950, before the attack. U.S. Department of Defense (DOD) records show that 326,863 troops were deployed in South Korea in 1953, a number that stabilized between 50,000 and 60,000 in the 1960s and the 1970s” [3]. As previously stated, the decrease in the deployment of U.S. troops overseas coincided with the escalation of the Cold War.

The Nixon administration’s goal of ending the Vietnam War led to a reduction in the number of U.S. troops, which had increased as a result of the intervention. During this process, discussions also included a reduction in U.S. forces in South Korea. Despite complex negotiations, South Korea ultimately agreed to the reduction of U.S. forces. The U.S. and South Korea continued to negotiate regarding the reduction of U.S. troops, even after the Nixon administration took office. Ultimately, they agreed to reduce the number of South Korean troops to 20,000. Since 1973, “U.S. troop levels in South Korea have remained relatively constant at roughly 35,000 to 40,000” [30]. According to the World Bank, Japan’s population in 2022 was 125,124,989, while South Korea’s was 51,628,117 [31]. Considering the population of those countries, it can be inferred that the presence of U.S. troops in South Korea since the end of the Cold War has been maintained due to the country’s strategic importance. As an alternative to reducing its U.S. troop presence, South Korea requested further U.S. military assistance. Although the Nixon administration was open to considering this option, the U.S. government never fully supported a military build-up for South Korea. Nixon’s administration may have believed that the presence of some U.S. military and nuclear weapons would function as a deterrent against a potential invasion by North Korea.

During the Korean War, there was a debate about the use of nuclear weapons, indicating that the U.S. government was considering this option. President Truman’s response to a reporter’s question was, “That includes every weapon that we have,” to a reporter’s question, “Will that include the atomic bomb?” This indicates that the administration considered this option during the war [32]. While the possibility of the Korean War escalating into a nuclear conflict increased, due to the U.S. use of nuclear weapons [33], it has never come to that point, and nuclear weapons have not been used in a war since the bombing of Japan.

Meanwhile, in Korea, according to Kristensen and Norris, in “January 1958, the U.S. deployed four (or possibly five) nuclear weapon systems with approximately 150 warheads” [34]. Although the objective of preventing a second Korean War resulting from South Korea’s continued confrontation with North Korea cannot be denied, it is more appropriate to consider the placement of U.S. nuclear weapons in South Korea as a factor in the deepening Cold War confrontation. This could be further exacerbated by nuclear cooperation between China and the Soviet Union–in other words, the U.S.-China conflict in East Asia. The U.S. deployed nuclear weapons in South Korea, as part of its extended deterrence policy, to provide a nuclear umbrella for its allies in the region. These weapons were relatively small and low-yield, designed for battlefield use, and included artillery shells and short-range missiles.

This decision was influenced by the expansion of tactical and operational possibilities, as well as the timing of international political détente, including the U.S.-China and Japan-China approach at the time. South Korea’s self-reliance efforts have led to the development of its own nuclear weapons program and even caused conflicts with the U.S. Although South Korea continued to receive military and economic aid from the U.S., it aimed to increase the independence of its defense capabilities by developing its domestic defense industry. South Korea’s self-defense policy includes training military personnel, improving equipment and weapons, building a reserve force, and developing nuclear weapons [35]. Regarding the latter, the U.S. maintained its nuclear umbrella policy. In 1972, President Park Chung-Hee secretly advanced a nuclear weapons program, which was eventually halted in 1977 due to President Carter’s threat to terminate it [36]. During this period, South Korea did not ratify the NPT until April 1975 [37].

However, in an effort to improve relations with China, the U.S. began reducing nuclear weapons housed with its East Asian allies. “The number of U.S. tactical nuclear weapons in South Korea declined from approximately 640 in 1974 to 150 in 1982, a significant reduction for which there are different explanations” [33]. Notably, this reduction was not solely due to the expansion of tactical operational possibilities. In the realm of international politics, it is possible to consider the period of international political détente, such as the approaches taken by the U.S. toward China and Japan. As a result of broader geopolitical changes after the end of the Cold War, the removal of nuclear weapons from South Korea was completed in 1991. In the early 1990s, global efforts to reduce the number of nuclear weapons followed agreements between the U.S. and the Soviet Union, such as the Intermediate-Range Nuclear Forces (INF) Treaty of 1987 and the Strategic Arms Reduction Treaty (START I) of 1991 [38]. In 1991, President George H. W. Bush announced the withdrawal of all U.S. tactical nuclear weapons deployed abroad, including those in South Korea. This was considered a confidence-building measure and a step toward the promotion of denuclearization and stability in the Korean Peninsula [39].

5. An ambitious framework for collective security

As mentioned previously, South Korea’s efforts toward self-reliance, which began prior to the Nixon administration’s policy shift, were overshadowed by a different approach: multilateral cooperation among Asia-Pacific countries. In 1964, the South Korean Government proposed the establishment of the Asian and Pacific Council (ASPAC) to promote regional cooperation and unity between the Asian and Pacific nations. Through the establishment of ASPAC, the proposal sought to strengthen regional cooperation and solidarity between the Asian and Pacific nations. Former South Korean foreign minister Lee Tong Won proposed this idea during his tour of the Republic of China, the Philippines, Thailand, South Vietnam, Malaysia, Australia, New Zealand, and Japan. A preliminary meeting was held in Bangkok in March 1965, with the participation of ambassadors from these countries.

A year later, the first ASPAC ministerial meeting took place on June 14, 1966, in Seoul. Foreign ministers from Australia, the Republic of China, Japan, Malaysia, New Zealand, the Philippines, Thailand, and South Vietnam attended the meeting, along with an observer from Laos [40]. Nine non-communist Asian and Pacific nations declared their determination to preserve their integrity and sovereignty in the face of external threats. The council invited other countries to join the newly formed ASPAC [41]. Their objectives were not limited to fostering development and mutual cooperation among the participating countries; they also included preventing the expansion of communist forces into East and Southeast Asia. This included providing support for South Vietnam during the Vietnam War.

ASPAC’s discussions focused on its initial objectives for the period following its establishment. For example, during the second session of the ASPAC ministerial meeting held in Bangkok from July 5–7, 1967, members decided to establish a cultural and social Center for the Asian and Pacific Regions [42]. At the same time, in August 1967, Indonesia, Malaysia, the Philippines, Singapore, and Thailand founded the Association of Southeast Asian Nations (ASEAN), which aimed to promote peace and security in Southeast Asia while fostering economic growth, social progress, and cultural development [43]. This may have encouraged South Korea to take further initiatives toward collective security cooperation. The fourth meeting of the council took place in Kawana in June 1969, following the third meeting of ASPAC, held in Canberra in August 1968. Members discussed security-related topics as South Korea had hoped. The most pressing security-related topics included the threat situation on the Korean Peninsula, the threat posed by China, the Vietnam War, the Soviet advancement into Southeast Asia, the implementation of U.S. defense policy, and regional security issues [44].

However, at the fourth ministerial meeting of ASPAC held in Japan, South Korea’s position was not endorsed, except for a statement opposing “aggressive acts” toward the ROK. South Korea “was less successful in its efforts to promote a PATO” (Pacific Area Treaty Organization) on the lines of NATO” [45]. During the U.S.-South Korea talks prior to the fourth ASPAC meeting, it was predicted that the collective security initiative proposed by the South Korean government and other Asian countries would not be effective. When Ambassador Kim Dong Jo, Secretary of State, met with William P. Rogers as Nixon’s Secretary of State on March 19, 1969, in Washington, Kim said, “There had been discussions among his colleagues about possibly extending an invitation to the U.S. to join [Asian and Pacific Council]. He wondered what the Secretary’s reaction might be to such a thought. The Secretary said that he did not think it was wise to consider this possibility. He felt that the Congressional reaction to further engagement, even of this sort, would be negative” [46].

Since then, the U.S. has consistently taken a negative stance toward any efforts by South Korea to engage in multilateral security cooperation, even involving the U.S. For example, the December 1970 National Intelligence Estimate stated that South Korea would continue to press for every opportunity to form a regional security alliance. The report also added that “in the past, it has tried such approaches as a PATO” modeled on NATO (which some South Koreans seem to believe commits the U.S. to automatic response in West Europe’s defense), an ABM system with the U.S. providing the weaponry and the countries within the range of Chinese missiles the real estate, a security system among the countries contributing troops to the Allied side in Vietnam, or expansion of ASPAC into a military alliance.¹ However, at the time, stated, that they “believe the central South Korean aim—is not so much to improve cooperation with Asian neighbors as to get the U.S. ever more securely bound to South Korea’s defense” [47].

The background of U.S. reluctance, and even a negative attitude, toward the Korean collective security concept stemmed from the Nixon administration’s endeavors to enhance U.S.–China relations. As relations between China and the Soviet Union deteriorated, the expansion of Soviet influence, not only in Southeast Asian countries but also in Taiwan, could not be ruled out. Henry Kissinger, the President’s National Security Advisor at the time, wrote: “The Soviet Union sought to expand its contacts with non-Communist Asian nations; feelers were even extended to Taiwan. In a campaign to thwart any Chinese effort to break out of its isolation, Soviet diplomats hinted that to isolate China better, the Soviet Union was prepared to avoid complicating relations with the U.S.” [48].

This U.S. position was also manifested in relations between Japan and the U.S. For example, during the meeting between the U.S. and Japan on June 2, 1969, the memorandum of conversation stated:

Aichi agreed absolutely that Japan should cooperate with the U.S. in the context of the relationship of mutual trust to contribute to peace and stability in Asia. On June 8, the foreign ministers of the ASPAC nations met in Kawana, Japan, to promote regional cooperation further. However, as the president knew, Japan’s Constitution was unique with respect to defense; it severely restricted overseas military cooperation by Japan. He [Kiichi Aichi served as the Minister for Foreign Affairs at the time] also hoped that the president would consider Japan’s unique views on nuclear weapons, which were derived from the fact that Japan was the only country to have suffered from their use [49].

When the possibility of U.S. troop withdrawal became a reality, with the announcement of the Nixon Doctrine, South Korea was still considering cooperation with Japan, in intelligence and military exercises, and a mutual defense treaty to fill the security vacuum. Japan’s efforts to strengthen its military and expand its security policy were met with flexibility by President Park. In his 1971 New Year’s address, President Park stated: “Japan is not a threat to Korea, and Korea does not object to Japan’s military expansion in the Asia-Pacific region” [50].

Upon closer examination, it appears that, while the APAC organization holds a common stance against communism, there may be varying perspectives within the group that warrant additional investigation. According to studies by Kei Koga, “although the image of the institution was strongly associated with anti-communist [sic] due to its membership structure and the strong anti-communist stance of ROK which proposed its establishment, several members including Australia and Japan avoided being stigmatized as such and promoted political dialogs as well as socio-economic functional cooperation only, rather than military cooperation” [51]. These efforts by Korea, along with essential changes in the regional situation, particularly the multilateral security concept, came to a standstill. Efforts to improve relations with China were initiated by the Nixon administration’s August 1971 declaration. However, Japan acted more promptly than South Korea.

In December 1971, Japan and China opened trade liaison offices to discuss the possibility of restoring diplomatic and commercial relations. In February 1972, Nixon and his delegation visited China, bringing relations closer to improving. In the same year, Park expressed his commitment to enhancing collective security [52]. However, in May 1972, North Korean journalists were authorized to enter Japan, raising concerns about the détente in Asia. In September 1972, the newly appointed Prime Minister Kakuei Tanaka visited China for a Japan-China summit meeting and signed a joint statement. The joint statement normalized diplomatic relations between Japan and China. Japan acknowledged its responsibility for the enormous damage caused to the Chinese people during World War II, and China renounced its claim for war reparations from Japan. It supported the “One-China” policy, as expressed in the Shanghai Communiqué between the U.S. and China, which states that Taiwan is an inalienable part of China’s territory [53]. Soon after the communiqué was issued, the Taiwan’s Foreign Minister, “Chow Shu-kal likens the communiqué that marked the end of President Nixon’s visit to the mainland to typhoon of the kind that smacks Taiwan every summer,” and he stated that “a storm has hit us” [54]. The economic relations between the two countries developed rapidly after the Vietnam War ended with the withdrawal of U.S. troops in March 1973. Subsequently, the ASPAC meetings were suspended in June 1973, “when recognition of China and withdrawal of representation to Taiwan led to the withdrawal of Malaysia and Australia; but some organizations set up continue to function” [55].

6. Conclusion

Following the Nixon administration’s shift in foreign policy, it took nearly a decade to establish formal diplomatic relations with China. The end of the Vietnam War and progress in U.S.-Soviet nuclear disarmament negotiations were among the positive developments during this period. The renewed Sino-Soviet rivalry and the Sino-Vietnamese war were among the negative developments. As the regional situation changed, South Korea opposed U.S. troop reductions. It did not support U.S. and Japanese efforts to improve relations with China. Similarly, Taiwan did not support the improvement of its relations with China. Consequently, as the Nixon administration moved forward with policy changes, its East Asian allies became increasingly anxious and dissatisfied with their security. In response, the countries explored the option of developing nuclear weapons and initiated programs toward that goal. As previously mentioned, South Korea downsized one-third of its U.S. forces, and Taiwan eventually withdrew all U.S. combat troops. In view of these circumstances, it is possible that South Korea and Taiwan may have a greater tendency to develop nuclear weapons than Japan. This of course portends badly for hoped of advancing the cause of global peace.

Japan, as the only country in East Asia to do so, expressed support for the U.S. objective of improving relations with China. As a result, Prime Minister Tanaka Kakuei visited China in September 1972, met with Mao Zedong and Zhou Enlai, and established diplomatic relations with the People’s Republic of China. Diplomatic relations with the Republic of China were severed as a result of this decision. On December 15, 1978, the U.S. and China jointly announced the establishment of diplomatic relations, effective January 1, 1979 [56]. Throughout the 1970s, Japan, the U.S., and China established multilateral relations in East Asia. This cooperation continued into the 1980s, with both the U.S. and Japan rapidly developing relations with China. South Korea sought to establish a multilateral East Asian security community with Japan, the U.S., and Korea at its core. Despite efforts, however, this goal was not achieved.

With the collapse of the Soviet Union in December 1991, the Cold War came to an end. The relations between North and South Korea developed rapidly between 1991 and 1992. China and South Korea normalized their relationships in August 1992. However, unlike the situation at the end of the Cold War in Europe, the regional situation in East Asia remained complex. Potential tensions and conflicts still exist between China and Taiwan and between North and South Korea. It is debatable whether stable multilateralism can be achieved in East Asia, given China’s adherence to a socialist system and North Korea’s unabashed advocacy of socialism. Although the U.S. and China both disapprove of the emergence of hegemonic powers in the region, China has become the second-largest economic power after the U.S., both in name and reality. China is also making further efforts on the military front. Multilateralism has undoubtedly expanded since the Nixon administration; however, whether further expansion is feasible remains a matter of debate.

The geopolitical situation in East Asia during the 2020s has become increasingly tense. A traditional Cold War-type confrontation structure is advancing further, with Japan, the U.S., and South Korea in conflict with China, Russia, and North Korea [57]. It can be said that the maintenance of the U.S.-led world order since the end of the Cold War is coming to an end, and conflicts in various regions are becoming more prominent. In 2022, conflict erupted in Ukraine due to Russian aggression, and the entire European region became more closely aligned with NATO’s sphere of influence. From the following year, significant changes took place in the Middle East. In East Asia, tensions between China and Taiwan are on the rise, and the situation on the Korean Peninsula is also becoming more increasingly tense. Furthermore, there have been simmering tensions between China and Southeast Asian countries. The self-reliance or self-help movements promoted by the countries of the East Asian alliance are ending, and multilateralism is now leading to conflict among various powers. During periods of regional deterioration, establishing a framework that unites more countries is crucial. This will benefit not only the region but also contribute to global peace.

Acknowledgments

This work was supported by JSPS KAKENHI (grant number 23 K11563).

Conflict of interest

The authors declare no conflict of interest.

Suat Utku Ay

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