The Association of Southeast Asian Nations (ASEAN), home to some 635 million people and a collective gross domestic product of nearly $2.6 trillion, is one of the largest economic blocs in the developing world. Its importance in the global economy will likely only grow in the coming decades as economic, military and political might shifts from Europe to the Asia-Pacific region. Much of that power, however, will be concentrated among the bloc's neighbors — namely, China, Japan and India — whose economies dwarf those of ASEAN states in both size and scope. They, and external powers such as the United States, will jockey for influence in Southeast Asia, creating a competition that could drive ASEAN members closer together in search of mutual protection. Yet the same contest may also aggravate the differences that have historically prevented the bloc from fully unifying.
The political barriers that divide ASEAN today are a consequence of the geographic barriers scattered throughout Southeast Asia. The Malay Archipelago is composed of thousands of tiny islands inhabited by a variety of ethnic groups. Steep mountains and dense forests disrupt transportation among them, isolating the region's ethnically, religiously and linguistically diverse populations from one another. Continental Southeast Asia, meanwhile, is split down the middle by several river systems running north to south, severing the connections between the region's eastern and western halves.
The core of Southeast Asia stretches from peninsular Malaysia, through Singapore, to the island of Java. It includes the metropolises of Greater Kuala Lumpur, Singapore, Batam, Johor and Jakarta, as well as the rest of Java, which alone accounts for roughly a quarter of ASEAN's collective GDP. Sizable cities exist beyond this region — Bangkok, Ho Chi Minh City, Hanoi, Manila and Yangon, to name a few — but each is largely secluded from the others, creating a natural gulf between Southeast Asia's continental and maritime countries.
As competition within the Asia-Pacific region heats up in the coming decades, the fissures within ASEAN will likely become more pronounced. The bloc's maritime members — the Philippines, Indonesia, Singapore, Malaysia, Vietnam and Brunei — will all seek to strengthen their relationships with countries that can help them counter China's naval encroachment in the region, including the United States, Japan and India. By comparison, continental Cambodia, Laos and Myanmar will continue to move closer to China. Moreover, because these states receive more direct investment in areas such as infrastructure, the gap between them and their maritime peers will probably widen. As it does, the bloc's "all or none" approach to policymaking will become increasingly unsustainable. And as long as its members continue to act in accordance with their own interests, the chances of a more united and cohesive ASEAN emerging from the version than exists today will be slim.