Some argue that ASEAN is both toothless and clueless in responding to these changes. Seen as ‘talk shops’, ASEAN’s regional institutions — the ASEAN Regional Forum (ARF), ASEAN+3, ASEAN+6 and the East Asian Summit (EAS) — might have been sufficient when great-power relations were less volatile right after the Cold War, but they have outlived their usefulness. ‘ASEAN centrality’, and even its very survival, is being written off.

But this critique misses a major point. ASEAN’s challenges are less about its external environment than strains in internal cohesion and capacity. The external environment actually reinforces ASEAN’s security role. If unity holds and it scales back its ambitions, ASEAN can survive and play an effective role in managing great-power competition, at least in Southeast Asia.

Traditional perspectives on the nature of great-power politics are helpful in understand ASEAN’s role in the region. John Mearsheimer argues that rising powers must expand to survive, often leading them to seek regional hegemony and provoking conflict. Others argue that international stability is a function of the number of great powers and the distribution of capabilities among them. A multipolar system is more prone to instability and conflict than a bipolar or unipolar one.

These perspectives would point to a bleak future for ASEAN. Chinese regional hegemony, whether coercive or benign, is bad news. It would certainly cover at least parts of Southeast Asia, including South China Sea claimants. A multipolar system dominated by great powers also gives little space to smaller, weaker states.

Chinese moves in the South and East China Seas and Russian moves in Ukraine give credence to this view of the world. Some see these developments as signs of expansionism, a ‘return of geopolitics’ and the resurrection of nineteenth-century European geopolitics in Asia.

There are alternative interpretations of what is happening in the world. Hedley Bull stressed the special responsibility of the great powers in managing international order. Karl Deutsch and David Singer rejected the idea that multipolarity invariably leads to great-power competition and conflict. It may make a potential aggressor less sure about its alignments and the size and power of a countervailing coalition.

At the core of all these ideas is the assumption of great-power primacy in maintaining stability. None recognises the influence of smaller, weaker players on great-power politics. If traditional perspectives were correct, ASEAN would have been doomed from its birth in 1967.

ASEAN is an anomaly. It has contributed significantly to reducing and managing conflict in Southeast Asia. Asia is now the only region in history where the strong live in the world of the weak, and the weak lead the strong. Its record may have been mixed, but the experience of ASEAN turns traditional realism on its head.

Today the phrase ‘great-power rivalry’ is misleading. Significant and far-reaching cooperation exists at the regional and global levels. This is underpinned by a type of interdependence that did not exist a century ago.

The term multipolarity is also out of date. It referred mainly to the number of actors and the distribution of power among them, but it said much less about the substance and quality of their interactions. The dominant feature of the world and Asia today is not multipolarity but multiplexity.

A multiplex world differs greatly from a multipolar system. Actors are not just great powers or nation states, but international institutions, non-governmental organisations, multinational corporations and transnational networks.

A multiplex order is marked by complex global and regional linkages. Trade, finance and transnational production networks were sparse in pre-World War European economic interdependence. Interdependence today goes beyond economics, covering the environment, disease, human rights, social media and a range of other issues.

Multiplexity means multiple layers of governance. Regionalism is a key part of this, but regionalism today is open and overlapping. This is a far cry from nineteenth-century imperial blocs that fuelled great-power competition and war. While power hierarchies remain, the overall architecture is non-hegemonic. Global hegemons are less viable. US hegemony is retreat. China is not going to replace it. A multiplex world encourages pluralistic and shared leadership. ASEAN’s prospects should be judged in terms of these unfolding changes towards a multiplex world.

There is currently no alternative to ASEAN’s convening power in Asia. The Asia Pacific’s great powers are not capable of leading Asian regional institutions because of mutual mistrust and a lack of legitimacy. Renewed great-power competition actually supports ‘ASEAN centrality’. China’s Asian Infrastructure Investment Bank may challenge the principle of ASEAN centrality, but Chinese initiatives are qualified by China’s problems in regional political and security issues.

ASEAN cannot take full advantage of this without unity or leadership. Its impact will be limited if domestic politics constrains key members. So ASEAN needs to downsize its agenda to revitalise. It needs to focus on urgent issues within Southeast Asia’s immediate environment and forget about the Korean peninsula, the Taiwan Strait and India–Pakistan conflicts. As the convener and agenda-setter at the ARF and EAS, ASEAN should focus attention on the South China Sea, no matter what China says, while sharing more responsibilities with middle powers on transnational and global challenges.

Predictions of ASEAN’s marginalisation have all proven to be exaggerated. It emerged stronger because it stepped up its act to cope with new strategic developments. Changing course now would compromise ASEAN’s inner strength.

Amitav Acharya is the UNESCO chair in Transnational Challenges and Governance and professor of international relations at the School of International Service, American University, Washington.

An extended version of this article appeared in the recent edition of the East Asia Forum Quarterly, ‘Japan–China Relations’.