There is no doubt the aspiration to a world free of nuclear weapons is a good one. For Australia, it’s the right thing to aim for, but it’s also in our national interest. The world is safer, and our region more stable, in a world where the number of nuclear weapons is falling.

Against that aspiration, the Non-Proliferation of Nuclear Weapons Treaty has been one of the world’s great diplomatic and legal successes. Not only banning proliferation, but, through Article VI, aiming to eliminate nuclear weapons as well, the Treaty has seen the global stockpile of fall 85 per cent since it was signed.

While the Treaty has worked more effectively in the past than at present, the trend is clear: the number of nuclear weapons has fallen dramatically since the end of the Cold War.

The Treaty has worked because the nuclear weapons states are members. The Treaty works because it is a shared expression of the shared goals of the countries that need to take action if those goals are to be met.

This is a crucial difference between the Non-Proliferation Treaty and the emerging push for a Treaty on the Prohibition of Nuclear Weapons. The first is an agreement between the countries that need to take action to do so. The latter is an agreement by countries that don’t have to take action that others should.

ANZUS today has evolved from its beginning as an agreement to respond to threats to one focused on the strategic aspirations and purposes of both countries.

The Prohibition Treaty is a cause which has little prospect of achieving our goal of a nuclear-free world but might undermine a cause which does. In addition, the Prohibition Treaty raises serious security issues for Australia, and impacts on our long-term relationship with the US.

In armed conflicts over more than a century, the military forces of Australia and the US have worked together for our shared strategic interests. The principal expression of our sense of common security purpose is the ANZUS Treaty.

ANZUS today has evolved from its beginning as an agreement to respond to threats to one focused on the strategic aspirations and purposes of both countries.

This is nowhere more clear than in the arrangements introduced at the Australia-US Joint Facilities, where integrated Australian and US staffs make the facilities truly ‘joint’.

The original purpose of the Joint Facilities – collecting signals intelligence – has expanded to include a key role in monitoring arms control agreements, among other things. With the continued growth of technical capacity, the Joint Facilities now permit the US and Australia greater operational integration.

As Kim Beazley, who re-shaped ANZUS in this way from the Australian side, wrote a short while ago, “[Since the end of the Cold War] it’s the steady integration of Pine Gap within our own intelligence and armed services operations that has marked a real functional change. It is now as vital for us as it is for the Americans”.

From Australia’s perspective, the Prohibition Treaty poses a serious question: it raises the prospect of Australia needing to repudiate our longstanding defence relationship with the US. Article 18 of the Prohibition Treaty appears to call into the question the validity the North Atlantic Treaty, the ANZUS Treaty, the US-Philippines Mutual Defense Treaty or the US-Republic of Korea Mutual Defense Treaty, since they would be deemed inconsistent with the Prohibition Treaty. This network of treaties has been, and continues to be, the security blanket under which Australia and much of our region sleeps.

What’s at stake here is whether Australia and the other allies of the US could, in the face of possible threats from other nuclear armed states, continue to incorporate US extended nuclear deterrence within their national security policies in the face of the Prohibition Treaty.

What’s at stake here is whether Australia and the other allies of the US could, in the face of possible threats from other nuclear armed states, continue to incorporate US extended nuclear deterrence within their national security policies in the face of the Prohibition Treaty.

The ANZUS Treaty requires Australia and the US to consult if threatened and to act to meet the common danger if subject to an armed attack. At face value, this may not appear to run counter to the Prohibition Treaty. But the fact is that the ANZUS Treaty provides the principal treaty cover for a raft of agreements, cooperative arrangements and memoranda of understanding that have underpinned Australia’s security policy for over 60 years. These extend from intelligence sharing agreements, acquisition contracts, logistic support, training exchanges and technical arrangements to facilities and basing agreements. Some of these agreements extend to technical capabilities that are intrinsic to monitoring and verifying major arms control agreements like the Strategic Arms Reduction Treaty and the Intermediate-Range Nuclear Forces Treaty.

This web of defence arrangements, built under the ANZUS Treaty, is at the heart of Australia’s defence.

We are living in a time of disruption where the operating rules of the past 70 years are under challenge. In that environment it is hard to justify an Australian government signing a treaty that might undermine one of the long-standing relationships working to improve Australia’s national security.