As a whole, Southeast Asia has had one of the longest historical relationships with China. However, modern relations between China and Southeast Asia only began after the Second World War. In China, the Communist Revolution succeeded in establishing the People’s Republic in 1949, while in Southeast Asia, the ensuing years of decolonization — whether violent or peaceful — resulted in the founding of several nation-states, each with vastly different cultural heritages, demographic compositions, levels of economic development, political systems and ideological persuasions. Since then, China-Southeast Asia relations can be roughly categorized into four periods.
 

1950s to mid-1970s: Early Cold War

This period corresponded with the development of the Cold War. From the 1950s to the early 1960s, relations between China and Southeast Asian countries could be categorized into three macro-themes. First was an ideological and military alliance between China and the North Vietnamese communists. Second were the relationships with non-communist but friendly regimes, which included Burma, Cambodia, and Indonesia. These countries also avowedly followed a neutrality-based foreign policy, but with very different interpretations of what “neutrality” meant. Third were relationships with hostile, anti-communist countries with which China had no formal diplomatic ties. In Indochina, these included the Kingdom of Laos and South Vietnam, and in maritime Southeast Asia these included Malaysia, Singapore, the Philippines and Thailand, all of which were militarily allied with Western powers through different security structures such as, for instance, the Southeast Asia Treaty Organization (SEATO) and the Anglo-Malayan Defense Agreement. These maritime countries, together with Indonesia, in 1967 formed the Association of Southeast Asian Nations (ASEAN), which was at times perceived by China as a tool of imperialism.

In the mid-1960s the geopolitical picture changed, with Indonesia and Cambodia experiencing coups that removed China-friendly leaders (and replaced them with anti-Chinese leaders). At the same time, China’s aggressive foreign policy damaged relations with Burma. By the early 1970s China found itself having very few friends in Southeast Asia. Even its communist allies, North Vietnam and the Pathet Lao, moved closer to China’s then rival: the Soviet Union.
 

Mid-1970s to early 1990s: The Second Cold War

These setbacks were compensated for when three maritime Southeast Asian countries –Malaysia, Thailand and the Philippines – began a diplomatic rapprochement with China in the mid-1970s. The most important factor contributing to these countries’ rapprochement with China was the perception of a strategic withdrawal of traditional Western powers (especially the US) and the need to cultivate ties with the largest communist power in Asia. The end of the Vietnam War in 1975 was soon followed by a drastic deterioration of China-Vietnam ties. Both China and ASEAN countries saw Vietnam’s removal of the Khmer Rouge regime in the late 1970s as proof of a hegemonic Vietnamese design for Indochina and the whole region. China launched an attack on Vietnam in 1979, and the entire region was thrown into what historians call Southeast Asia’s “Second Cold War”.

In the last decade of the Cold War, there was a complete overturn in China’s alliances. China’s earlier allies (Vietnamese and Laotian communists) had now become adversaries, while its earlier foes, the pro-Western maritime Southeast Asian countries (now grouped together in ASEAN), became partners to keep Vietnam’s  expansion in Indochina under control. However, beyond this common strategic objective, distrust and suspicions still prevailed between China and individual ASEAN countries, most notably between Indonesia and China. Thailand conversely was the ASEAN country that most welcomed this newfound friendship with China.
 

Early 1990s to 2010s: Post Cold War and Golden Decade

The end of the Cold War got off to a fresh start. China established diplomatic ties with two remaining members of ASEAN, Indonesia and Singapore, in 1990. With the Cambodian crisis coming to an end, there was a normalization of China’s ties with Laos and Vietnam and China-Southeast Asia relations shifted from focusing on security coordination to real, substantive cooperative partnerships. With the Cold War ending, the South China Sea issue emerged to become a more salient security issue between China and Southeast Asia, especially between claimant states. Still, throughout the first two decades of the post-Cold War era, security no longer was the most important factor influencing China’s relations with Southeast Asian countries.

In light of the expansion of ASEAN to include Indochinese countries and Myanmar, China’s relations with Southeast Asia need to be examined by looking at China’s interactions with the organization. In 1991 China was invited to attend an ASEAN summit, and in 1996 it became ASEAN’s dialogue partner. In ASEAN, China found a friendly and neutral organization where it learned to use regional multilateral diplomacy. Moreover, China was feeling comfortable with the “ASEAN Way”. Consequently, there was a rapid development of China-ASEAN ties. China acceded to ASEAN’s Treaty of Amity of Cooperation (TAC), formed a Strategic Partnership with ASEAN, participated in all ASEAN-led regional security structures (ASEAN Regional Forum, ASEAN plus Three, East Asia Summit, ASEAN Defense Ministers Meeting Plus) and created the China-ASEAN Free Trade Area. Regarding the South China Sea issue, the Declaration on the Conduct of Parties in the South China Sea (2002) greatly stabilized the dispute. The year 2006 was even designated the Year of China-ASEAN Friendship and Cooperation. In addition, China also enhanced its reputation among ASEAN countries in the 1997-1998 Asian financial crisis by pledging not to devalue its currency and supporting the Chiang Mai Initiative (CMI), a multilateral currency swap arrangement.

Official Chinese rhetoric calls the first decade of the twenty-first century the “Golden Decade” between China and ASEAN. These were indeed the best years for their relations, since with the US distracted by its global War on Terror, there was a widespread perception that the US’ influence was declining significantly in comparison with China’s.
 

2010s to the present: the beginning of a “New Era”

The “Golden Decade” did not continue. Chinese foreign policy shifted from one of “keeping a low profile” into one that was more proactive and assertive. While the shift in Chinese foreign policy began earlier than Xi Jinping’s ascent to the top leadership position in 2012, Xi’s “China Dream” rhetoric offered a nationalist justification for Chinese foreign policy. The South China Sea dispute became a major concern. China’s relations with the Philippines and Vietnam deteriorated significantly after 2013 and 2014 due to escalations in the South China Sea dispute. Even Malaysia, traditionally a more China-friendly claimant state, found reasons to worry about China’s strategic intentions. China was believed to practice “divide-and-rule”, enticing its close partners in ASEAN to prevent a unified position in ASEAN. Due to this dispute, much of the strategic trust between China and ASEAN countries built up during the “Golden Decade” was wiped out.

Southeast Asian countries are not pivoting away from China amidst the intensifying rivalry between the US and China. Economically many of them continue to embrace China. Xi’s signature foreign economic policy, the Belt and Road Initiative also found varying degrees of acceptance in ASEAN countries, many of them hungry for greater Chinese investment in infrastructure and manufacturing.

Xi has defined his era as the “New Era”. This new era promotes a vision of China being the leader of a “community of shared destiny”. So far, Southeast Asian countries remain cautious of fully accepting, let alone embracing, the Chinese vision. The deepening of economic cooperation with China has often been balanced by a security relationship with the US. Hedging continues to define the way Southeast Asian countries respond to China’s rise, albeit with increasingly narrower room to maneuver.