The US strike on three Iranian nuclear facilities has ended 10 days of uncertainty and signalled a shift in the Middle East’s strategic dynamic. While Israeli Prime Minister Benjamin Netanyahu has tempered his rhetoric on regime change, Iran is likely to respond, and what follows remains unclear.

How Iran responds will depend heavily on the capability it has left. In recent weeks, Israel hasn’t just targeted nuclear and energy infrastructure, but struck weapons facilities, missile launchers and air defence systems.

Meanwhile, Iran has spent two years exporting drones to Russia, further straining its own stockpiles. Analysts doubt the effectiveness of Iran’s missile arsenal, with many suggesting a large number either failed to launch or fell short of their targets.

Iran has several avenues for retaliation, each carrying different risks. Striking US bases in the Middle East, such as the Fifth Fleet headquarters in Bahrain, or targeting Gulf States seen as softer options would be at the extreme end of the spectrum and almost certainly draw in more regional and global actors. Such a move would likely undermine what must now be Iran’s top priority: regime survival.

More limited responses, such as attacks on US facilities in Iraq or Syria, would follow familiar patterns of Iranian behaviour. An escalation into the maritime domain is plausible. In 2019, for example, Iran targeted commercial shipping in the Gulf in response to the US withdrawal from the Joint Comprehensive Plan of Action under President Donald Trump and increased sanctions, a tactic it has used repeatedly since the 1979 revolution.

Any disruption to traffic through the Strait of Hormuz—through which nearly 30 percent of the world’s oil flows—or a long-threatened closure by Iran would have direct consequences for Australia. As a country that imports 91 percent of its fuel, much of it refined from Middle Eastern crude, Australia remains highly exposed to trade interruptions. Despite this, Australia holds less than the International Energy Agency’s mandated 90-day fuel reserve, just 56 days as of March 2025. It’s why the Royal Australian Navy spent nearly 30 years contributing to coalition maritime security operations in the region.

Beyond the implications for Australia’s fuel security, the US strikes on Iran carry another significant consequence for the Indo-Pacific: the message they send to China about US resolve. While some analysts have expressed concern that renewed US engagement in the Middle East could distract from its primary theatre, the Indo-Pacific, particularly as ships, missile batteries and aircraft are redeployed, the strikes may also help re-establish US deterrence. As Secretary of Defense Pete Hegseth reaffirmed, the Indo-Pacific remains the United States’ strategic priority.

As many have noted throughout Russia’s war in Ukraine, what happens in one region directly shapes the strategic environment in another, particularly in the Indo-Pacific. How China assesses its prospects for taking Taiwan, or advancing other territorial claims, is influenced by the global response to aggression elsewhere.

While international statements of support for Ukraine were strong, the actual flow of weapons was often slow and constrained. Until late 2024, the US and others placed significant restrictions on Ukraine’s ability to strike targets inside Russia and ruled out escalatory steps such as a no-fly zone. That limited resolve, despite Ukraine’s determination, emboldened Vladimir Putin and likely China.

Since Russia’s invasion of Ukraine in 2022, supported economically and technologically by China, Beijing has grown increasingly emboldened in the Indo-Pacific. This has been evident in more aggressive joint military exercises simulating the encirclement of Taiwan, accompanied by propaganda depicting missile strikes on the island.

In the South China Sea, China’s coercive behaviour has escalated, including the ramming and water-cannoning of Philippine vessels operating within the Philippines’ exclusive economic zone. Chinese forces have also increasingly conducted unsafe and unprofessional intercepts of military aircraft and ships, including those from Australia.

However they are ultimately judged, the US strikes on Iran go some way toward re-establishing deterrence in the Indo-Pacific. Just as the muted international response to Russia’s invasion of Ukraine likely emboldened China, this action sends a clearer message: there are limits. Despite concerns about the current administration’s policies on NATO, Ukraine and tariffs, the US is not retreating into isolationism. Where its national interests are threatened, as in the case of Iran’s pursuit of nuclear weapons, the US is still willing to act, particularly in support of its allies.

The re-establishment of deterrence in the Indo-Pacific, a key priority reaffirmed by Hegseth at the recent Shangri-La Dialogue, is likely reinforced by the US strikes on Iran. But Australia must also play its part. One clear warning from the current Middle East conflict is that the world is changing: states are increasingly turning to military force to advance national objectives. If Australia is to contribute to regional deterrence and, if necessary, respond to protect its national interests, it must go beyond rhetoric. That means addressing our strategic resilience, starting with fuel stockpiles, and rapidly lifting defence spending and capability to meet the demands of this more dangerous era.

This article was originally published by The Australian.