Trump's 2025 shake-up of the world order has put the Indo-Pacific balance of power back in play

While President Donald Trump’s mixed signals did not lead to a summary US disengagement with the region, they did prompt regional actors to look less towards Washington for security guarantees and more to the building of diversified networks of cooperation.

The impact of Trump 2.0: The year saw a stark turn in US engagement, with Trump’s approach to the Indo-Pacific characterized by unpredictability at best and rent-seeking at worst.

The recently-released US National Security Strategy was emblematic of this ambiguity, prioritizing quid pro quo ties over legacy commitments and the use of muscular rhetoric while offering little doctrinal clarity.

This has sent out mixed signals on China, as its deterrence rhetoric coexists with policy fuzziness and even deference in some parts, with US partners struggling to identify US thresholds for action, particularly on high-stakes issues such as Taiwan.

Despite the rhetorical turbulence emanating from Washington, alliance architectures did not collapse, although they didn’t sprint forward either.

Traditional security partnerships with Japan, Australia, South Korea and the Philippines have endured amid a sobering realization of the magnitude of US capabilities, particularly vis-à-vis strategic concerns about China.

Nonetheless, the pace and predictability of strategic cooperation have waned, which is telling in the context of a tenuous regional landscape.

Hence, although formal alliances will continue to matter, their political meaning has shifted, with partner countries less willing now to outsource strategy entirely to Washington and more inclined to shape outcomes independently, reflecting a post-‘hub-and-spokes complacency’ mindset.

Similarly, multilateral formats like the Quad persisted and adapted, but the coherence of their agenda often reflected leadership from partners as much as from Washington.

Initiatives such as maritime domain awareness and cooperation on critical minerals, for example, were driven more on the ground by Canberra, New Delhi and Tokyo, with Washington’s role being facilitative rather than directive.

Regional agency: Perhaps the most consequential development this year was the agency exercised by regional actors in response to what was increasingly perceived as systemic uncertainty. For Asean, this pattern has progressively reinforced hedging.

Southeast Asian capitals simultaneously deepened economic ties with China while engaging in strategic projects with Western partners, seeking leverage rather than compliance with any single power bloc, even as some of them strengthened their responses to Beijing’s intensifying maritime assertions.

The diversification of bilateral cooperation formats, such as the one between Indonesia and France, illustrated how middle powers are constructing multiple poles of engagement to mitigate overdependence on either Washington or Beijing.

This was supplemented by Vietnam’s deepening defence ties with India, particularly in maritime capacity building and naval training, the Philippines’ calibrated outreach to both the US and non-traditional partners such as Japan, India and South Korea, and Malaysia’s renewed engagement with China and the EU simultaneously.

All of this reflected the pursuit of new hedging strategies.

In East Asia, Japan and South Korea pitched themselves not merely as US partners, but as proactive architects of regional security norms and economic linkages.

Tokyo’s calls for sustained US commitment were matched with its own investments in Asean alongside an expansion of defence and strategic cooperation. Taiwan, caught between US inconsistency and Beijing’s growing military muscle, embodied the precariousness of regional agency.

Taipei doubled down on diversifying economic alliances and seeking soft security assurances in its notably nuanced adaptation to the evolving order.

In the meantime, India strengthened and expanded its bilateral partnerships across Southeast Asia as part of its broader Indo-Pacific engagement, particularly with Thailand, the Philippines, Vietnam, Singapore and Indonesia, expanding cooperation across defence, renewable energy, critical technologies, maritime safety, technology and trade.

Taken together, these moves signal that New Delhi’s engagement with Southeast Asia in 2025 was more proactive, institutionally embedded and regionally resonant than in prior years.

Going forward: A contested equilibrium characterizes the Indo-Pacific’s emerging order. As countries recalibrate their strategies to manage risk independently, they are investing in deterrence, resilience and interoperability. This has prompted defence modernization, arms diversification and indigenous capacity building.

What 2025 underscored is that the Indo-Pacific is shedding illusions about US leadership and instead focusing on negotiating a more complex, contested and agency-driven regional architecture.

The upshot of this is not stability in the traditional sense, but managed fluidity where power is more diffused, agency is more distributed and outcomes are more contingent.

The authors are, respectively, vice president for studies and associate fellow for Indo-Pacific, Observer Research Foundation