SOUTHEAST Asia’s diplomacy with China cannot be left to 11 separate national calculations. Geography and commerce bind the region to China, but power is unequal. Alone, members face Chinese inducements or pressure without regional support. Asean needs multilateral diplomacy to establish what its members will uphold together. Smaller groups can then solve focused problems without weakening that common position. Otherwise, Asean risks being picked off one member at a time, even while its summits continue to proclaim unity.
The multilateral foundation is Asean centrality: the discipline of agreeing on principles before engaging China. The Asean-China Plan of Action for 2026–2030 provides a framework spanning security, economic, social, environmental and cultural cooperation. Asean should use it to set priorities, review implementation and benefit communities. The upgraded Asean-China free trade agreement reaches digital and green economies alongside trade. Separate investment offers can tempt governments to mute objections. Members need shared standards on transparency and resilience so economic cooperation strengthens rather than fragments their negotiating position.
The South China Sea shows why a common position matters. Persistent disputes make dialogue indispensable, but dialogue cannot mean leaving a state alone when its lawful rights are challenged. Asean should agree in advance how to report incidents, affirm the United Nations Convention on the Law of the Sea and respond collectively to coercive conduct. It should press China for a substantive, effective Code of Conduct that reduces dangerous encounters, protects lawful rights and provides crisis procedures. A code must not dilute international law or restrict states outside the negotiations. Collective statements need not settle every sovereignty claim. They can establish that pressure against one member concerns the region as a whole, while keeping channels open for de-escalation.
Consensus among 11 states can be slow, especially when their exposure to China differs. That difficulty makes preparation more important, not collective diplomacy less necessary. Coastal states with overlapping concerns can coordinate legal analysis, share maritime information, establish coast guard hotlines, and agree on search and rescue, fisheries protection and incident reporting. Such groups should feed their findings into Asean, building a stronger regional position. Where China is ready, they can cooperate on marine science, conservation and safe navigation. The test is whether practical cooperation reinforces Asean’s shared principles when those principles come under pressure.
Diplomacy should operate across tracks to make that collective position informed and durable. Track 1 brings officials to formal negotiations. Track 1.5 brings officials together with researchers and practitioners. Track 2 lets scholars, civic groups, business, labor, youth and local governments explore proposals before governments adopt them. Think tanks can test options for a maritime code, environmental safeguards or labor standards. Fisheries communities can describe risks official maps miss. Local administrators can compare flood warnings, disaster response and public health programs. These channels help governments negotiate with knowledge and public legitimacy. Asean Plus Three shows discussion can extend beyond summits.
Soft diplomacy also supports regional cohesion. Cultural exchange, education, journalism and youth programs connect neighbors. Asean and China have formal cultural cooperation arrangements and have highlighted people-to-people exchanges. Such programs should create reciprocal opportunities: joint research, scholarships across disciplines, artist residencies, school partnerships, heritage preservation and regional reporting fellowships. Participants should come from rural communities and minority groups as well as capitals and elite universities. Honest cultural exchange can build trust, while independent media literacy and open discussion help societies resist stereotypes and disinformation without surrendering scrutiny of state conduct.
Social diplomacy matters because people experience geopolitics through livelihoods and safety. Governments can cooperate on migrant worker protection, trafficking, online scam networks, public health, food security, disaster preparedness and education. These problems hit vulnerable people first. Asean and China should create practical channels among labor ministries, police, health agencies and civil society, with safeguards for rights and due process. Smaller groups can pilot hotlines, worker information services or disaster drills in border regions, then bring the lessons to Asean for common standards. Success should be judged by safer workers, faster assistance and more secure communities. A shared regional agenda can also prevent protection from depending on any government’s bilateral favor.
Environmental diplomacy is equally urgent. Forest fires and haze, river flows, marine plastics, biodiversity loss, extreme heat and stronger storms ignore national boundaries. The Asean-China environmental strategy for 2026–2030 identifies cooperation in green technology, circular economy, finance and alignment of trade with climate commitments. Asean should insist on open environmental data, independent monitoring, community consultation and measurable targets across projects, including those negotiated bilaterally. Mekong countries can pursue basin-level cooperation on timely hydrological data and ecological impacts, while coastal states and China can expand scientific work on shared marine ecosystems. Every project should disclose who benefits, who bears costs and how affected communities can seek remedy.
Multilateral diplomacy must set the region’s floor: international law, peaceful settlement, inclusive institutions and standards no member will quietly trade away. Minilateral cooperation can help directly affected states move sooner, provided their work returns to Asean and raises its capacity to act. Bilateral engagement remains necessary for specific disputes and agreements. But if each government treats a concession as its private gain or a maritime incident as another state’s private problem, China can deal with them one by one. Asean needs consultations before negotiations, information on proposed agreements and a habit of responding when any member faces pressure. Common principles acquire force only when members defend them together.
The test is not whether Asean can erase its differences with China. It cannot. The test is whether those differences will let a much larger power choose the terms of engagement separately with each member. Asean will negotiate collectively, coordinate selectively, speak candidly and cooperate where interests converge. It can pair credible defense and legal positions with open economic exchange, social protection, ecological stewardship and genuine cultural contact. Diplomacy across all tracks gives Southeast Asia more ways to shape outcomes, but its center must hold. If Asean will not stand behind its own common positions, members become easier to isolate. Unity must be practiced before the next crisis, not merely invoked during one.
The author is a professor at UP Los Baños and vice chairman of the board of PTVNI.
