The Philippines contains vital terrain in maritime Southeast Asia, for the US and its regional allies. The Philippines is also worth defending, in normative terms, as a democracy of approximately 115 million people whose sovereignty is under daily challenge from an expansionist authoritarian power, China, which has fixed the Philippines in its strategic crosshairs. The positional importance of the Philippines coupled with its revived treaty alliance with the US makes it pivotal to deterring aggression against Taiwan and other parts of what US strategists call the First Island Chain. Australia has independent reasons to be invested in the security of the Philippines beyond its importance to US strategy in the Indo-Pacific region.
The Marcos administration is actively bolstering Manila's other security partnerships. Australia's defence relationship with the Philippines has evolved considerably since 2017 to become Manila's closest security relationship after the US. In fact, Canberra is currently more closely aligned with Manila than it is with Washington. Closer alignment reflects shared threat perceptions as well as a wider inter-alliance, cross-bracing trend that's driven, in part, by shared doubts about the US commitment to its allies' security. Making a military contribution to the defence of the Philippines against external aggression entails additional strategic risk for Canberra, as it's the most likely scenario to embroil the ADF in a US–China conflict. But it's in Australia's independent interest to do so, as part of an international coalition, in defence of the regional order and a democracy under direct threat.
This report first analyses the forcing factors that have brought about strategic convergence between Australia and the Philippines. Second, it explains why a political window has opened for institutionalising defence cooperation with the Philippines. Third, it assesses a recent joint defence exercise (Alon 2025) in light of a planned upgrade to the bilateral defence relationship. Finally, in this context, it offers policy recommendations to both governments for furthering defence ties.
