ANZUS, for example, was not originally intended to be a nuclear security arrangement, and there is no mention of the word ‘nuclear’ in any of its provisions. This treaty has, however, been consistently interpreted by successive Australian governments as providing nuclear protection for Australia, with no objection from the US. Arguably, this amounts to ‘subsequent practice’ under the rules of treaty law and has the effect of changing the legal nature of the security alliance to one that encompasses nuclear protection. Given that ANZUS started out as a conventional security alliance, there is no legal reason why it could not be renegotiated or reinterpreted to prevent the use of nuclear weapons. Rethinking nuclear security alliances would not be easy, but it is possible, and is likely the only way that nuclear umbrella states like Australia can become parties to the TPNW without otherwise withdrawing from such alliances.
Why not harness the groundswell of local support for the TPNW to pressure governments into renegotiating the terms of their security treaties? By engaging with the security narrative a little more closely, anti-nuclear advocates might be able to address, and ultimately delegitimise, some of the resistance towards the TPNW and move a little closer to the humanitarian goal of a world free from nuclear weapons.