Fit for Purpose: Can Southeast Asian Minilateralism Deter?

In examining the development of minilaterals anchored in Southeast Asia, this essay considers whether and, if so, how this subregion could contribute to broader capabilities to deter military aggression. The essay argues that Southeast Asia's experience with minilateralism is much more limited, focused, and functionally driven by specific security challenges such as armed robbery. It is unlikely that Southeast Asian states will be comfortable with a broader minilateral arrangement involving extraregional powers designed to deter China or sideline existing mechanisms led by the Association of Southeast Asian Nations (ASEAN). For better or worse, a more limited and functionally driven minilateralism gives Southeast Asian states more control over the direction, scope, and quality of cooperation. As well, analysts from the subregion have warned of the possibility that Indo-Pacific minilateral arrangements could become platforms for major powers to extend their influence.¹

The essay is divided into three parts. First, it provides an overview of the recent history of minilateralism in Southeast Asia, with a focus on the Malacca Straits Patrol (MSP) between Indonesia, Singapore, Malaysia, and Thailand as well as trilateral security cooperation between Indonesia, Malaysia, and the Philippines. It also briefly notes other experiences of minilateralism involving Southeast Asian states beyond the security realm. Next, the essay highlights the different features of minilateralism anchored in Southeast Asia in contrast to U.S.-anchored minilateralism and assesses the likelihood of Southeast Asian–led arrangements contributing to a broader deterrence effort against China. Finally, the essay offers several policy considerations regarding whether and, if so, how Southeast Asian–led minilateralism can be of strategic salience in the Indo-Pacific security landscape.

Southeast Asian–Anchored Minilateralism

In the Indo-Pacific context, minilateralism generally refers to cooperative relations between a group of three to nine countries that are relatively exclusive, flexible, functional, and often informal in nature.² Such arrangements should theoretically be nimbler while providing targeted approaches to address specific challenges in ways that existing mechanisms cannot.³ The "task orientation" of minilateralism also typically renders such groups less threatening to states that perceive themselves to be the target of containment strategies or that have values and interests that depart substantially from perceived multilateral agendas.⁴

Minilateral security cooperation varies based on the grouping's size, goals, processes, and relation to existing arrangements.⁵ Different major powers, such as the United States and China, also support their own versions of minilateralism. U.S.-anchored minilateralism, for example, has been designed to complement the United States' Cold War–era system of bilateral alliances with a web of new security mechanisms.⁶ Indeed, the United States remains the central hub, although not necessarily the initiator, in recent minilateral arrangements (e.g., the Quad and AUKUS), backed by a broader strategic framework likely centered on or aimed at China. The strategic asymmetry of power is also another key feature in such U.S.-anchored minilateral arrangements.

But Southeast Asian–anchored minilateral experiences differ. For one, many of the minilateral arrangements in Southeast Asia have been driven by limited functional and security needs. Governments also welcome minilateral arrangements where they are equal veto players, not a subordinated spoke to a more powerful hub. Symmetry of power is a priority in Southeast Asian minilateral arrangements, although it is not always achieved. For these reasons, Southeast Asian states have been reluctant to engage in minilateral arrangements outside of ASEAN or in those that are directed against China.

Minilateral security arrangements involving only Southeast Asian states have become more prominent over the past two decades. Initially, minilateral groupings that proliferated in the 1990s in this subregion were economically rather than security focused. The Singapore-Johor-Riau Growth Triangle, for example, was created in 1989 and later expanded in 1994 to facilitate cross-border trade and investment flows between Singapore, Malaysia, and Indonesia. Around the same time, the Brunei Darussalam–Indonesia–Malaysia–Philippines East ASEAN Growth Area was launched to increase trade, tourism, and investment by facilitating the free movement of people, goods, and services.⁷ The Asian Development Bank–backed Greater Mekong Subregion (GMS) was founded in 1992 with Cambodia...