ANZUS: the only invocation of the Australia-New Zealand-US treaty came after 9/11

Background

In the news: Australia marked 25 years since Operation Slipper, its first military contribution to the war in Afghanistan. ANZUS is the Security Treaty between Australia, New Zealand and the United States of America, in effect since 1952. Article IV states that an armed attack in the Pacific Area on any of the Parties would be dangerous to its own peace and safety. On 14 September 2001, after the 11 September attacks, Prime Minister John Howard announced, after consulting the United States, that Article IV applied. The Parliamentary Library describes this as the first, and so far the only, invocation of the treaty. The first Australian troops departed on 22 October 2001 to join US-led operations, and all ADF personnel had left Afghanistan by July 2021.