Abstract
The ANZUS alliance represented an important pillar in the United States’ web of alliances during the Cold War. ANZUS was at the time the primary vehicle for securing the South Pacific. But between 1984 and 1987, the alliance would be thrown into chaos following the election of David Lange and the Fourth Labour government in New Zealand, with the promise to ban all ships carrying nuclear weapons from NZ ports. This chaos would conclude with Washington suspending security obligations towards New Zealand and ending the overwhelming majority of bilateral defence and security cooperation, even as Wellington enshrined a policy banning entry by nuclear-armed and nuclear-propelled warships into NZ ports as legislation.
This thesis answers the question: why did the United States suspend its security obligations towards New Zealand under ANZUS? The thesis will construct a neoclassical realist theory, focused on the structural decline of the Cold War US-Soviet competition, which in turn impacted both perceptions of threat and domestic political pressures within New Zealand. These changes would eventually result in the suspension of security obligations by the United States. The thesis will draw on archival material from both New Zealand and the United States to recount the history of the ANZUS alliance, the nuclear-free movement in New Zealand, and the events of the crisis between 1984 and 1987. The thesis will then employ a process tracing methodology to test the developed neoclassical realist theory by comparing it to the events explored, before also examining the interpretations and limitations of three prominent theories of international relations: neorealism, constructivism, and liberal institutionalism.