Two months into the U.S.-Israel war against Iran, it may sound clichéd today to reiterate that geopolitical instability in West Asia (or the Middle East) creates ripple effects that affect Southeast Asia.
West and Southeast Asia: Common Strategic Interests
But it was something of a bellwether in 2025, when the Association of Southeast Asian Nations (ASEAN) established the first ASEAN-GCC-China Summit to institutionalise cross-regional cooperation. Dismissed by some political observers as more symbolic than substantive, the Summit nonetheless underscores the common strategic interests that connect these regions, particularly West Asia and Southeast Asia. If there is still doubt about these strategic interests, one needs only read the daily news about the socio-economic and political consequences of the U.S.-Israel-Iran war for Southeast Asia.
After the war broke out, ASEAN foreign ministers issued a statement on 4 March 2026 expressing their concerns. The statement also emphasises ASEAN countries’ commitment to utilising existing frameworks to provide emergency assistance to their citizens in West Asia affected by the war.
On 13 April 2026, ASEAN foreign ministers issued another statement calling for the full implementation of a ceasefire and expressing concern about the blockade of the Hormuz Strait. On the same day, the Philippines, which chairs ASEAN in 2026, issued a Chair’s statement that reiterated the war's impact on Southeast Asia and underscored the need to explore coordinated regional responses to strengthen collective resilience.
These statements demonstrate solidarity and highlight the regional mechanisms that ASEAN leaders should have the political will to mobilise to build collective resilience against food and energy security vulnerabilities. However, if the U.S., Israel, and Iran remain in a state of war and its global impact continues to unfold, ASEAN should also examine the implications for its political-security community.
More Dangerous Times Ahead for ASEAN
It is possible that the U.S.-Israel-Iran war could become another catalyst for further weakening the rules-based international order and a harbinger of more conflicts. For example, in an interview with CNBC on 22 April 2026, Singapore’s Foreign Minister Vivian Balakrishnan warned that the blockade of the Hormuz Strait would look like a “dry run” if China and the U.S. went to war in the Indo-Pacific.
Even now, after the U.S. forces intercepted three Iran-linked tankers in waters near India, Sri Lanka and Malaysia in April 2026, there remains a risk that the U.S.-Iran maritime confrontation could spread to Southeast Asian strategic waterways. Further geopolitical complications could arise if U.S. forces intercept more Iran-linked tankers, not only to weaken the Iranian regime but also to sever China’s access to Iranian oil. This scenario sits alongside the possible threat of Iran-linked attacks against American and Israeli interests in the region, especially in Singapore, which has longstanding relations with Israel and the U.S.
Against this backdrop, what issues associated with the U.S.-Israel-Iran war could shape the strategic environment in which ASEAN militaries operate? What impediments to regional solidarity and stronger security cooperation could be ASEAN’s Achilles heel if the Indo-Pacific faces heightened geopolitical tensions or, worse, becomes a theatre of military conflict involving the major powers?
Is ASEAN Defence Prepared for a More Unstable World?
These are pertinent and potentially sensitive questions that ASEAN officials, particularly those in the defence sector, should examine more deeply during upcoming ADMM (ASEAN Defence Ministers' Meeting)-related meetings. At least three broad issue areas come to mind: military diplomacy, military preparedness, and cyber defence.
Firstly, the U.S.-Israel-Iran war has revealed some differences in policies and attitudes among ASEAN countries in managing its impact. For example, Singapore cited the right of transit passage under the United Nations Convention on the Law of the Sea (UNCLOS) and therefore refused to negotiate with Iran for safe passage through the Hormuz Strait. This position differs from that of Indonesia, Malaysia, the Philippines, and Thailand, which have been in talks with Iran. Another difference in attitude over the control of strategic waterways emerged when the Indonesian Finance Minister proposed charging tolls on vessels passing through the Straits of Malacca and Singapore. Together, these issues raise the question of whether conflicts initiated by major powers would unite ASEAN countries or sow division, with implications for military diplomacy in Southeast Asia.
Secondly, the U.S.-Israel-Iran war has heightened the urgency for ASEAN countries to modernise their warfighting capabilities to enhance military preparedness in an increasingly dangerous world. As European arms suppliers struggle to support Ukraine and match the industrial capacity of their adversary (Russia), the reliability of an unpredictable U.S. as an arms supplier and underwriter of Asia-Pacific security cannot be taken for granted. Consequently, there may be greater calls to implement the ASEAN Defence Industry Collaboration (ADIC) initiative, established by the ADMM in 2011. But will differing attitudes among ASEAN countries towards the U.S.-Israel-Iran war add to differences in geopolitical inclinations that have been impeding ADIC’s progress?
Thirdly, ADMM has begun efforts to enhance ASEAN militaries’ capacity to implement the United Nations Norms of Responsible State Behaviour in Cyberspace. A stable cyberspace is crucial for ASEAN as it aims to sign the ASEAN Digital Economy Framework Agreement (DEFA) in 2026. However, the use of cyber operations alongside kinetic warfare in the U.S.-Israel-Iran war suggests that the breakdown of the rules-based international order also occurs in cyberspace. Therefore, will cyber norms, in addition to the current state of cyber defence cooperation among ASEAN countries, effectively protect the region against cyber threats if conflict occurs in the Indo-Pacific?
In conclusion, the U.S.-Israel-Iran war is another example of how distant wars, such as those in West Asia, have a strategic impact on Southeast Asia. It could raise many questions about the region’s collective resilience. Additionally, the political-security dimension of this impact warrants further examination, as does the question of whether the ASEAN defence sector is well-positioned to protect the region’s interests in an era where conflicts are more likely.
