• ASEAN is in danger of becoming marginalized as East Asian security becomes increasingly shaped by such volatile flashpoints as a nuclear North Korea and a South China Sea increasingly dominated by quarrels over sovereignty and maritime security.

• Accordingly, the notion of “ASEAN centrality” is now being seriously challenged and is unlikely to prevail against the growing bipolar security environment shaped by China and the United States.

• ASEAN and other Asia-Pacific states could gravitate toward one of five alternative order-building scenarios: (i) A Sino-American condominium that defines and accepts each other's geopolitical sphere of influence; (ii) The replacement or substantial revision of the United States’ bilateral alliance system with the expansion of multilateral norms and instrumentalities; (iii) The gradual predominance of an “Asia for Asians” concept led by China but endorsed by a substantial number of Southeast Asian states; (iv) Effective balancing and hedging by smaller states and “middle powers”, leading to eventual great power acceptance of a regional power equilibrium; (v) An intensification of regional “community building” via an amorphous but wide-ranging series of economic, ideological and strategic compromises to make war unthinkable and to strengthen regional interdependence.

• However, none of these five scenarios is likely to predominate in a literal sense. Instead, the “realist” explanation for understanding security in the region is the most accurate forecast for understanding an East Asian security environment that is becoming increasingly disorderly.

• ASEAN can still play a constructive — if not central — role in shaping East Asia's strategic environment by working with China and the United States to strengthen confidence-building in regional security politics and to encourage their respect for strategic constraint.