At the United Nations last month, Australia formally ended five years of opposition to the 2017 Treaty on the Prohibition of Nuclear Weapons. Rather than voting against an annual UN General Assembly resolution urging countries to join the landmark treaty – as it had done in previous years under the former conservative government – Australia abstained for the first time. Campaigners welcomed this shift as a “small but important step forward”.

Indonesia and New Zealand, two of Australia’s closest neighbours, also praised the move. The Indonesian ambassador to Canberra, Siswo Pramono, said the change would “give encouragement to others to believe that we are on the right path” in seeking a world free of nuclear weapons: “Your voice matters. Your stance matters.” New Zealand’s foreign ministry said it was “pleased to observe a positive shift” in Australia’s position and “would, of course, welcome any new ratifications as an important step to achieving a nuclear-weapon-free world”.

But this week the United States warned Australia against joining the treaty, arguing it could hamper defence arrangements with its allies, as the treaty “would not allow for US extended deterrence relationships, which are still necessary for international peace and security”. It added: “The United States does not believe that progress toward nuclear disarmament can be decoupled from the prevailing security threats in today’s world.”

ICAN Australia’s director, Gem Romuld, said Australia must make its own decision on joining the TPNW based on the will of the Australian people. “It’s no surprise that the US don’t want their allies to sign on, because if we claim protection from their so-called ‘nuclear umbrella’ then it helps justify their continued retention and possible use of these illegal and indiscriminate  weapons,” she said. An opinion poll in March found 76 per cent of Australians support signing the TPNW, with 6 per cent opposed and 18 per cent undecided.

Until last month’s UN vote, Australia was the only member of a regional nuclear-weapon-free zone treaty to oppose the annual resolution on the TPNW. Nuclear weapon-free zones cover 116 countries, including those of Southeast Asia and the South Pacific – many of which were instrumental in the negotiation and adoption of the TPNW in 2017. Under the 1985 South Pacific Nuclear Free Zone Treaty, Australia has accepted a legally binding obligation never to acquire nuclear weapons or host them on its territory.

Following the election of a Labor government this May, Australia began a reassessment of its position on the TPNW. According to the foreign ministry, it is examining a number of important questions “to inform [Australia’s] approach to the TPNW in close consultation with partners, and civil society stakeholders”. Specifically, it is “taking account of the need to ensure an effective verification and enforcement architecture, interaction of the [TPNW] with the Nuclear Non-Proliferation Treaty (NPT) and achieving universal support”.

The review is based on a resolution adopted by the Australian Labor Party at its national conference in 2018, which committed the party to sign and ratify the TPNW in government after taking account of the above factors. Anthony Albanese, who now serves as prime minister and has been a vocal supporter of the TPNW, initiated the resolution. He said at the time: “Our commitment to sign and ratify the nuclear weapon ban treaty in government is Labor at its best.” The party formally reaffirmed its position in 2021.

Three in four federal Labor parliamentarians, including Mr Albanese, have also individually pledged to work for Australia’s signature and ratification of the TPNW. So too have parliamentarians from the Australian Greens and other parties. In September, 10 independent federal parliamentarians issued a joint statement urging the Labor government to “make use of every opportunity to advance Australia’s position in support of the [TPNW]”, and a cross-party parliamentary friendship group for the TPNW was formed.

As evidence of the Labor government’s professed “constructive engagement” with the TPNW, Australia attended as an observer the first meeting of states parties to the TPNW in Vienna in June. Susan Templeman, a Labor parliamentarian, headed the official delegation. Ahead of the meeting, 55 former Australian ambassadors and high commissioners sent a letter to the prime minister urging him to act swiftly on Labor’s pre-election pledge to sign and ratify the treaty.

“Membership of the TPNW is compatible with Australia’s alliance commitments and will make a positive contribution to the security objectives we share,” they wrote. “We have previously signed and ratified treaties – on landmines, cluster munitions and nuclear testing – to which the United States is not a party.” Notably, three other countries in the Asia–Pacific region that the United States has designated as major non-NATO allies are TPNW states parties: New Zealand, the Philippines and Thailand.

The new Australian government has said that it “shares the ambition of TPNW states parties of a world without nuclear weapons and is committed to engaging constructively to identify possible pathways towards nuclear disarmament”. Its decision to attend the first meeting of states parties, its abstention on the recent UN vote, and its ongoing engagement with civil society organisations, including ICAN, reflect this commitment.

While a formal cabinet-level decision to support and join the TPNW is still pending, the Labor government’s initial steps in this direction are cause for optimism. “We look forward to a formal decision by the Albanese government to sign and ratify the TPNW – in line with its pre-election pledge,” said Ms Romuld. “The overwhelming majority of Australians support joining this treaty, and progress towards disarmament is more urgent than ever.”