Canberra can no longer assume that Washington will underpin regional stability or the rules-based order, the foundational premise of modern Australian strategic planning. Australian policymakers must grapple with the prospect that the destabilising behaviour of US President Donald Trump’s administration is not temporary.

It is prudent to start considering the unthinkable sooner rather than later and plan for a possible world where the anchor of our security architecture continues rewriting that architecture in unexpected ways.

Over the past twelve months, a scenario once deemed implausible has materialised: three great powers—Russia, China and the United States—are simultaneously challenging the rules-based order.

Australia’s strategic guidance documents produced over the past decade—including the 2016 Defence White Paper, 2020 Defence Strategic Update and 2024 National Security Strategy—anticipated and grappled with Moscow and Beijing’s revisionism. However, Washington’s ongoing transformation from guarantor to disruptor represents a fundamental break in Australian strategic planning.

Trump’s threats towards NATO allies including Denmark have undermined trust. The imposition of visa processing pauses on security partners such as Thailand has perturbed long-term partners. And senior US officials embracing a might-is-right doctrine demonstrates the US has moved beyond rhetoric and is operationalising a policy of dismantling the rules-based order.

Critics will argue this overstates the threat and that it risks becoming a self-fulfilling prophecy that weakens the alliance. However, there is great danger in assuming that the US will, at an unspecified date in the future, return to its historical role as a stabilising force, either globally or particularly in the Indo-Pacific. As Malcolm Turnbull, prime minister when the 2016 Defence White Paper was released, wrote in 2024: ‘many in Canberra will say, and will want to believe, that nothing has changed.’

Denying reality doesn’t change it. Lee Kuan Yew’s axiom of being guided by reason and reality rather than ideological commitment remains relevant. As Canadian Prime Minister Mark Carney declared at the 2026 Davos summit: ‘nostalgia is not a strategy’.

The first Trump presidency showed strong indications that the US’s interest in preserving post-war institutions was flagging, but those ambitions were largely frustrated by the Washington establishment. The Biden administration’s commitment to NATO and AUKUS now appear in hindsight as a temporary respite rather than a return to normalcy. The guardrails of the first Trump presidency now appear much diminished. The speed of events, the number of alienated partners, and Washington's willingness to coerce allies makes restoration of the pre-2016 order improbable.

While Australia shouldn’t stop working with the US as far as it can, it does need to consider strategic planning without reliable US leadership. To that end, three areas demand immediate attention and must be considered seriously—regardless of whether a more normal US administration comes to power in 2028.

First, Australia must accelerate domestic defence industrial capability, despite associated costs. The assumption that US supply chains will reliably deliver critical systems during crises no longer holds. Effective deterrence and resilience require both operational and industrial sovereignty. This means hard choices about domestic production. The March 2025 announcement of a guided weapons manufacturing facility in Newcastle represents a start, but the scale must increase dramatically.

Second, Australia needs to deepen regional partnerships to hedge against US unreliability. Japan and key Southeast Asian states must become genuine strategic alternatives, not supplements to the ANZUS alliance. This means expanding intelligence-sharing beyond Five Eyes frameworks, conducting more frequent military exercises without US participation, and developing independent deterrence architectures. Australia needs partnerships that can function when Washington is absent or actively hostile to regional stability. Fortunately, Australia is not alone, and many if not most of Washington’s historic allies are looking to deepen cooperation with like-minded partners.

Third, and perhaps most importantly, Australian defence planning must develop genuine strategic ambiguity and contingency plans for scenarios where Washington’s interests diverge from Australian interests. Strategic guidance in the 2010s and early 2020s assumed alignment with Washington. A realistic 2026 assessment cannot. This requires uncomfortable conversations about circumstances where Australia might need to act independently or even contrary to Washington’s preferences. What happens if Washington strikes a grand bargain with Beijing that sacrifices Australian interests? What if the US demands Australian participation in operations that destabilise rather than stabilise the region? Scenarios that may have seemed farfetched in 2016 or 2024 don’t in 2026.

As the US undergoes serious transformation, Australian security depends on whether Canberra can develop the partnerships, capabilities and strategic independence to navigate uncertain and highly unexpected developments.