In the second week of the escalating conflict between the United States, Israel and Iran, Australia on 10 March announced a limited contribution to help under-attack Gulf states detect and shoot down Iranian missiles and drones.

While the outcome of the conflict remains far from certain and few people would pretend to know how a war of this scale will unfold, Australia is right to support the US and the defence of the Gulf states under attack, within limits.

Within these limits is Australia’s contribution of an airborne early warning aircraft and air-to-air missiles to help defend Gulf partners from Iranian missile and drone attacks. Tehran has spent decades building the capability and networks needed to destabilise the region, threaten maritime trade and project coercion well beyond the Middle East.

Much of the Australian debate has focused narrowly on whether the use of force complies with international law. That question matters. But a binary fixation on the letter of the law risks missing the broader strategic reality: Iran’s behaviour has long posed a challenge that the international community has struggled to address decisively.

Under the United Nations Charter, the lawful use of force is confined to two situations: self-defence or authorisation by the UN Security Council. While legal scholars debate the boundaries of collective or pre-emptive self-defence, actions that fall outside those criteria are meant to sit within the authority of the Security Council.

Historically, the Security Council has authorised major military action, including the defence of South Korea in 1950 and the liberation of Kuwait during the first Gulf War in 1991. But in 2026, the Security Council has largely ceased to function as an effective mechanism for responding to major threats to international peace and security.

This paralysis has been most obvious in Russia’s invasion of Ukraine, carried out by a permanent member of the Security Council itself. But it was evident earlier in the Security Council’s failure to prevent North Korea from developing nuclear weapons before its first test in 2006.

In the absence of a functioning Security Council, the international system lacks a clear mechanism to address emerging security threats. Iran has become one of those threats through both its advancing nuclear capabilities and the network of proxies it supports across the Middle East.

This is the delicate legal and political dance national leaders are now performing, one rarely stated openly. As Mark Carney observed at the World Economic Forum in Davos, ‘the story of the international rules-based order was partially false’.

International law has served middle powers such as Australia well, underpinning decades of security and prosperity. But there are moments when the legal framework struggles to deal with emerging threats. Even without a clear self-defence justification, action against Iran still serves Australia’s security interests.

This does not mean that might makes right, or that international law should be abandoned. But there are moments when the international system simply struggles to deal with regional and global threats.

It is in this context that degrading Iran’s military capability and proxy network is in Australia’s interests. The government’s position of qualified defensive support to the Gulf states is therefore the right one. Not because Australia automatically backs everything the US does, but because doing so advances Australia’s own security interests.

A limited Australian deployment to help defend Gulf states from Iranian missile and drone attacks would also be consistent with that approach. But the key word is limited.

Australia should not provide open-ended support. Lengthy Middle East commitments have often undermined Australian Defence Force preparedness and distracted from China’s growing military challenge in our region.

A targeted contribution helping detect and defend against missile and drone attacks on Gulf states is strategically sensible. A further naval contribution to help keep the Strait of Hormuz open, as Australia has done previously, would also support global trade and energy security. The strait remains one of the world’s most important maritime choke points.

Done properly, this approach allows Australia to achieve several objectives at once.

It can act as a global partner, support allies under pressure and gain valuable operational experience for ADF personnel in modern missile and drone warfare. That experience may prove increasingly important should Australia face a crisis or conflict in our own region.

But Australia’s limited number of deployable surface combatants means any maritime commitment must be weighed carefully.

With naval capability already stretched, sending ships to the Gulf would risk undermining preparedness for potential crises closer to home while offering only limited additional capability to the effort.

Washington has framed the campaign around four objectives: degrading Iran’s missile capability, destroying missile production infrastructure, weakening its naval forces and preventing it from acquiring nuclear weapons. These aims are largely achievable if the US avoids expanding the mission and if Iran is prevented from receiving resupply or industrial support from Russia or China.

If the conflict begins to move beyond these objectives, Australia should resist expanding its commitment, particularly through ground forces. Canberra must remain firmly focused on the Indo-Pacific.

War is always terrible. Wars that appear to arise from choice rather than clear necessity are often the most uncomfortable of all.

Yet a disciplined US intervention in Iran serves Australian, regional and global interests, even if it brings short-term economic costs. Australia should support its allies where our interests align. But we must also remain disciplined enough to preserve our limited military capability for crises closer to home.

This article was originally published in the Australian Financial Review.