On 1 September 1951, the ANZUS Treaty between Australia, New Zealand and the United States was signed in San Francisco.
The Australia, New Zealand, United States Security Treaty (ANZUS or ANZUS Treaty) is a collective security non-binding agreement between Australia and New Zealand and, separately, Australia and the United States, to co-operate on military matters in the Pacific Ocean region, although today the treaty is taken to relate to conflicts worldwide.
It provides that an armed attack on any of the three parties would be dangerous to the others, and that each should act to meet the common threat. It set up a committee of foreign ministers that can meet for consultation.
The treaty was one of the series that the United States formed in the 1949–1955 era as part of its collective response to the threat of communism during the Cold War.
New Zealand was suspended from ANZUS in 1986 as it initiated a nuclear-free zone in its territorial waters; in late 2012 New Zealand lifted a ban on visits by United States warships leading to a thawing in tensions.
New Zealand maintains a nuclear-free zone as part of its foreign policy and is partially suspended from ANZUS, as the United States maintains an ambiguous policy whether or not the warships carry nuclear weapons and operates numerous nuclear-powered aircraft carriers and submarines; however New Zealand resumed key areas of the ANZUS treaty in 2007.
In the years following the Second World War, Australia and New Zealand began pressing the United States for a formal security guarantee.
The two nations felt threatened by the possibility of a resurgent Japan and the spread of communism to their North. Additionally, the fall of Singapore in 1942 had demonstrated that their traditional protector, the United Kingdom, no longer had power in the region.
This added to their sense of vulnerability. The United States was initially reluctant, offering instead an informal guarantee of protection. But the need to strengthen the West against communism grew with the Communist victory in the Chinese Civil War in 1949 and the 1950-1953 Korean War.
Additionally, the United States wanted to gain Australian and New Zealand approval for a ‘soft peace’ with Japan. The treaty allayed antipodean fears that such a peace would allow Japan to threaten them again.
The resulting treaty was concluded at San Francisco on 1 September 1951, and entered into force on 29 April 1952. The treaty bound the signatories to recognise that an armed attack in the Pacific area on any of them would endanger the peace and safety of the others.
It stated ‘The Parties will consult together whenever in the opinion of any of them the territorial integrity, political independence or security of any of the Parties is threatened in the Pacific’. The three nations also pledged to maintain and develop individual and collective capabilities to resist attack.