The development of nuclear weapons has been a critical problem for the NATO alliance. In the Pacific, a region of increasing strategic interest for the United States and Soviet Union, nuclear weapons have been an environmental concern since the bombing of Hiroshima and Nagasaki. Opposition to nuclear tests has now been taken a step further with the creation of a South pacific Nuclear Free Zone and the decision by a New Zealand Government to ban port visits by vessels believed to be carrying nuclear weapons. New Zealand's proposal to back its policy with legislation had been seen by the Reagan and Thatcher administrations as a threat to the principle of 'neither confirm nor deny' the presence of nuclear weapons on vessels. This 1989 study examines the questions of principle at issue, the evolution of the ANZUS crisis, its implications for the Western alliance structure as a whole, and the degree to which the 'nuclear-free' virus' in the South Pacific might be catching.