Quad Expands Maritime Security Options in Southeast Asia

"A promising option, therefore, may be for Quad partners to pursue activities with more flexible participation," a Hoover Institution study published on 13 October concludes — and that sentence frames the strategic choice confronting Australia, India, Japan and the United States as they seek to work with Southeast Asian states on maritime security.

Three variables that determine regional acceptance

The study identifies three interactive variables that largely determine whether Southeast Asian governments will welcome Quad security initiatives: the character of the activity, the configuration of participating countries, and the activity’s geographic location. Activities that deliver tangible or capacity-building benefits — and that avoid signalling collective defence or bloc-building — are more likely to gain traction. By contrast, initiatives perceived as raising the risk of arms races or reprisals from Beijing are more likely to meet resistance.

Least-sensitive options: maritime domain awareness and HADR

The paper singles out maritime domain awareness and humanitarian assistance and disaster relief (HADR) as the least contentious areas for Quad activity. Two named programs illustrate that approach: the Indo‑Pacific Partnership for Maritime Domain Awareness and its complement, the Indo‑Pacific Maritime Surveillance Collaboration, both designed to aggregate a richer picture of illicit or threatening activities at sea. Similarly, the Quad’s Indo‑Pacific Logistics Network aims to speed the movement of personnel and supplies for relief operations; involving prospective recipient countries in exercises or pre‑positioning relief stocks at regional logistics nodes could broaden acceptance.

Combat training draws the most scrutiny — but nuance matters

Military activities intended to build combined combat capabilities are the most sensitive, yet the regional response is not monolithic. The paper notes the Philippines — described in the study as "a founding member of the Squad grouping with Australia, Japan and the US" — is already well disposed to deeper military cooperation. Indonesia and Singapore, meanwhile, might accept incremental expansions in conventional activities, such as field training exercises, depending on scale and scope. The study points to Talisman Sabre — the biennial Australia‑based exercise that included 19 countries, among them Quad members and Southeast Asian partners such as Indonesia, the Philippines, Singapore and Thailand — as an example of broader participation in major exercises.

Who leads matters: trade‑offs between the US and India

Who takes the lead in any initiative affects how it will be perceived. The study argues the United States brings the greatest military capability but is also most likely to provoke a stern response from China; it also notes that the Trump administration’s policy volatility has at times led some states — the study cites Indonesia — to view proximity to Washington as a form of insurance against unpredictability. India, by contrast, "lacks a sustained presence in maritime Southeast Asia east of the Malacca Strait," so India‑led efforts would probably register fewer political repercussions for risk‑sensitive states such as Vietnam, even though India offers fewer material benefits. The study recommends flexible participation — trilateral efforts, rotating leadership, or selective invitations to Southeast Asian states — to lower signalling risks and increase regional buy‑in.

Geography: Indian Ocean opportunities versus South China Sea sensitivities

Location changes the political calculus. Most Southeast Asian governments see activities in the contested waters of the South China Sea as highly contentious; the Indian Ocean, by contrast, is "far removed from competing maritime claims" and offers a less controversial arena for testing cooperation. The Quad has already piloted the Indo‑Pacific Maritime Surveillance Collaboration in the Indian Ocean. The authors emphasise framing: the same activity will be viewed differently if framed as constructive capacity building rather than as a step toward collective defence.

What this means for Indonesia, the Philippines, and Vietnam

- Indonesia: With President Prabowo Subianto described as taking greater control of foreign and defence policymaking, external proposals may be judged through presidential calculus that prioritises material returns; openings for unorthodox partnerships may be time‑limited if policymaking power shifts back to bureaucratic gatekeepers. - The Philippines: As a country already receptive to deeper military cooperation, it is more likely to accept expanded combat‑oriented activities if they are offered. - Vietnam: Given that "China’s actions…against neighbours such as Vietnam" are increasingly publicised, initiatives led by less provocative partners — the study suggests India — may be preferable to avoid escalation while still enhancing capability. The Quad’s leaders’ summit next month in Manila is flagged in the study as an immediate opportunity to consult directly with Southeast Asian partners — but the authors urge that it not be the last such engagement. Sustained, reciprocal consultation with ASEAN and individual regional governments, they argue, is the pathway to designing maritime security activities that deliver benefits to Southeast Asia while managing political risk. The central question the study leaves on the table is precise: will Quad partners use flexible participation, capacity‑building framing, and an Indian Ocean first approach to expand maritime security cooperation without fuelling regional fears of bloc formation? Continued, substantive consultation with Southeast Asian states will determine whether that strategy succeeds. Original: How the Quad can work with Southeast Asia — The Strategist / Australian Strategic Policy Institute