The chipped porcelain of the international order is showing cracks, and Southeast Asia finds itself bracing for a tremor. For decades, the region has operated under a largely unspoken agreement: Washington provides security architecture, Beijing provides economic leverage, and local nations navigate the space in between. That arrangement is fraying, not with a bang, but with a series of increasingly pointed silences from Washington regarding its commitments. The question isn’t *if* Southeast Asia must prepare for a world with diminished American guarantees, but *how*.

The Illusion of Evacuation: Beyond Logistical Planning

Recent war games, as highlighted by the International Institute for Strategic Studies, reveal a troubling tendency among Southeast Asian governments to view a potential Taiwan contingency through the narrow lens of citizen evacuation. The IISS report underscores that What we have is a fundamentally miscalculated approach. A crisis in the Taiwan Strait won’t conclude once foreign nationals are safely removed; it will *begin* a new, far more complex phase demanding strategic choices with lasting consequences. The focus must shift from exit strategies to positioning – a recognition that Southeast Asia will be a critical theater, regardless of diplomatic alignment.

This isn’t merely about access to airspace or waters, though those are significant concerns. It’s about the broader operational demands placed on nations caught between competing great powers. Will states sustain defense partnerships that risk censure from Beijing? Can they credibly deny access to critical infrastructure without provoking retaliation? These aren’t logistical puzzles; they are existential strategic questions.

The Waning of American Power and the Rise of Regional Self-Reliance

The erosion of domestic support for long-term US forward deployment is undeniable. The political landscape in Washington, regardless of party control, increasingly favors conditional burden-sharing and a reluctance to engage in open-ended global commitments. Michael Beckley’s analysis in *Foreign Affairs* details this shift, arguing that America’s “strange triumph” – its relative economic decline despite continued military strength – is driving a reassessment of its global role. This creates a dangerous ambiguity for Southeast Asia, exposed to both the risk of abandonment and the threat of coercion should they stray too close to Beijing.

expecting assistance from other regional powers is equally problematic. Japan, understandably, will prioritize the defense of its own interests, particularly Taiwan. India remains preoccupied with its continental disputes with China and Pakistan, and its strategic focus remains firmly fixed on the Indian Ocean. As Dr. Collin Koh Swee Lean, a research fellow at the S. Rajaratnam School of International Studies in Singapore, explains:

“Southeast Asia can no longer rely on a ‘security provider’ model. The expectation that another power will step in to guarantee their security is unrealistic. The region needs to move towards a model of ‘strategic autonomy,’ where states grab greater responsibility for their own defense and regional stability.”

Strategic Geography: Mapping the Lines of Contest

The answer isn’t a new ASEAN-based mechanism or a revival of Cold War-era collective defense pacts – those are politically untenable. Instead, Southeast Asia must fundamentally rethink how it approaches defense, moving beyond national-centric planning to a regional perspective. This doesn’t necessitate collective action or institutional coordination, but a shared understanding of strategic geography.

Specifically, nations must:

• Map key axes of advance through which external powers would project force into the region. This includes identifying critical sea lanes, air corridors, and potential landing zones.
• Identify key terrain, chokepoints (like the Strait of Malacca), and vulnerability cascades that shape the operational possibilities of external powers.
• Concentrate effort on positions each state can credibly hold without weakening its ability to defend its immediate approaches.

This approach prioritizes calculated self-defense over ideological alignment. It acknowledges that instability stemming from great-power competition further afield will inevitably compress the strategic depth available to countries further south, shrinking their buffer zones and exposing previously secure defensive lines. The Lowy Institute’s analysis emphasizes the need for a regional mindset, arguing that individual states can contribute to collective security simply by understanding and maximizing their own capabilities within the broader regional context.

The Anti-Access/Area Denial Paradox and the Need for Integration

Even as some Southeast Asian nations are developing anti-access/area denial (A2/AD) capabilities, these efforts are often fragmented and inward-looking. They are frequently shaped by internal security concerns rather than external defense requirements and rarely integrated into a broader regional picture. No single state can credibly execute a denial strategy on its own, and there’s limited evidence of sustained effort to develop such capacity at the minilateral or ASEAN level.

the effectiveness of A2/AD systems is often overstated. As a 2024 report by the US Department of Defense notes, the PLA is actively developing countermeasures to A2/AD systems, including advanced electronic warfare capabilities and long-range precision strike weapons. This underscores the need for a more holistic approach to defense, one that combines A2/AD with other capabilities, such as intelligence, surveillance, and reconnaissance (ISR), and cyber warfare.

As former Indonesian Defence Minister Ryamizard Ryacudu stated in a 2023 interview: “We must strengthen our own capabilities, not just rely on technology. We need to build a strong defense industry and train our personnel to be ready for any eventuality.”

Beyond Alignment and Neutrality: Managing Pressure, Not Choosing Sides

This regional approach doesn’t eliminate the choice between alignment and neutrality in a Taiwan contingency. However, it fundamentally alters the conditions under which those choices are made. By developing the capacity to manage the spillover pressures of great-power conflict – particularly demands over access, basing, and overflight – states can prevent operational necessity from dictating their foreign policy outcomes. They can delay, condition, or limit such demands, preserving their strategic autonomy.

A Taiwan contingency will inevitably impact Southeast Asia. The real question isn’t whether the region will be affected, but whether its nations can sustain their chosen positions under pressure. Without the capacity to manage that pressure, foreign policy becomes reactive, not strategic. The time for strategic calculation is now, before the tremors become an earthquake.

What steps will your nation take to prepare for a future where security guarantees are less certain? The conversation starts with acknowledging the shifting landscape and embracing a regional perspective.