Across Southeast Asia, the US-Israel military campaign against Iran is prompting a quiet but consequential reassessment of strategic alignments. While most governments in the region have publicly adopted stances of non-interference, behind the scenes they are accelerating efforts to diversify their security partnerships and reduce reliance on Washington.
The tension is visible in recent diplomatic friction between Jakarta and Washington. A new US-Indonesia defense agreement was followed by an apparent rift between Indonesia's defense and foreign ministries over granting the US overflight rights above the Strait of Malacca, resulting in a hold on access. The episode underscores a broader unease with President Donald Trump's transactional and unpredictable foreign policy, which has widened the divide between the United States and many Southeast Asian capitals.
Eroding Trust and Shifting Preferences
Though suggestions of a diminished US role in the region have circulated for years, they have not always been backed by concrete evidence. Successive American administrations managed to reassert engagement after periods of drift — from Barack Obama's "Pivot to Asia" to the Indo-Pacific strategy under the first Trump term and its continuation under Joe Biden. Today, however, the decline in US influence appears more pronounced.
One key indicator is the absence of unequivocal support from traditional allies during the Middle East crisis. Even Singapore, a longstanding security partner of the US, has voiced criticism. Foreign Minister Vivian Balakrishnan stated in late March: "I was surprised by the onset of hostilities. I did not think it was necessary. I do not think it is helpful. Even now, there are doubts about legality."
Another telling sign comes from the ISEAS-Yusof Ishak Institute's State of Southeast Asia 2026 survey. For the first time, a narrow majority of respondents — 52% — now favor alignment with China over the US. The margin is slim but significant. In Indonesia, 80% of respondents prefer Beijing; in Malaysia, 68%; in Singapore, 66%. Only 23% of Filipino respondents express a similar inclination, reflecting Manila's more assertive stance in the South China Sea.
Energy Shock and Economic Pressure
Two major factors are driving this recalibration. The most immediate is the disruption of the Strait of Hormuz, which has severely impacted ASEAN economies. According to the ASEAN Centre for Energy, Middle Eastern crude made up 56% of the bloc's total crude imports last year. The resulting energy shock is already visible: foreign investors are selling Thai assets amid concerns about price volatility linked to the US-Iran conflict. For a deeper look at how the crisis is affecting regional supply chains, see our analysis of Japan's supply chain strains.
The second factor is rapidly declining confidence in the US. Perceptions of unpredictability — from the imposition of tariffs to a lack of sustained economic and security focus on the Indo-Pacific — have reinforced doubts about Washington's reliability. Trump's temperamental approach to foreign policy has prompted a serious recalibration among allies and partners. With US attention and resources stretched across conflicts from Europe to the Middle East, and an America First doctrine at home and abroad, such a recalibration is both justified and understandable.
The apparent failure of the US to shield its Gulf partners from Iranian attacks serves as a grim reminder that self-reliance, complemented by credible strategic support from major powers, remains the ultimate guarantor of security. For many middle and small regional powers, the choice is no longer limited to the US or China. While trust in Washington is clearly in decline, it does not automatically translate into alignment with Beijing. Instead, most Southeast Asian countries are prioritizing flexibility and diversifying their strategic partnerships. Japan, Australia, India, Turkey, the United Kingdom and the European Union are seen as partners with untapped potential.
The US-China dynamic is often framed as benefiting Beijing, but that view is overly simplistic. Divisions within ASEAN persist, especially regarding the South China Sea. While China has frequently exploited differences among ASEAN members, this fragmentation also creates challenges for Beijing. The Philippines' more assertive stance, for example, has complicated China's efforts to maintain a consistent regional strategy. For more on how the conflict is reshaping regional security postures, see our report on nuclear energy and security reassessments.
The US-Israel-Iran conflict has made clear that ASEAN member states do not view it as their conflict. This has prompted a reassessment of their global positions and created space for more autonomous foreign policies. Crises can present opportunities. For many ASEAN states, this may be the moment to address internal divisions and pursue a more coherent, collective approach — one that strengthens the bloc and reduces vulnerability to external shocks.
Dr. Rahul Mishra is an associate professor at the Centre for Indo-Pacific Studies, School of International Studies, Jawaharlal Nehru University, New Delhi, India, and a senior research fellow at the German-Southeast Asian Center of Excellence for Public Policy and Good Governance, Thammasat University, Thailand. He is also the series editor for the Palgrave Series in Indo-Pacific Studies.
