ANZUS is a collective defense treaty formed by Australia, New Zealand, and the United States. The name combines the first letter of each word in the names of the member countries. Each of these countries declared that an armed attack in the Pacific area on any of the three nations would be dangerous to them all. Each nation pledged to “act to meet the common danger in accordance with its constitutional processes.” The treaty was signed in San Francisco on Sept. 1, 1951, and it became effective on April 29, 1952.
In 1984, the New Zealand government adopted a policy, and later a law, that excluded from its ports and territorial waters all nuclear-armed ships and ships powered by nuclear fuel. In response to this policy, the United States announced in 1986 that it would no longer guarantee New Zealand’s security under the ANZUS treaty. However, Australia continued to cooperate with New Zealand under the treaty.
