ANZUS

The Australia, New Zealand, United States Security Treaty (ANZUS) is a collective security agreement between Australia, New Zealand, and the United States that was signed in 1951, and from which New Zealand has been partially suspended since 1986. 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.