Chapter 3 establishes the nexus between South African policies on the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) and their defiance thereof, and the continued parallel development of nuclear weapons. Drawing on recently declassified documents, I trace the national position of the South African government on NPT accession and the application of IAEA safeguards over the 1980s. Most importantly, the focus lies on domestic decision-making and how a small number of people in the South African government decided whether to sign the NPT. This also includes a careful analysis of Pretoria’s relations with the US government under President Ronald Reagan and related exchanges with the IAEA Secretariat under its Director-General Hans Blix, developing in parallel over the period from 1981 to 1988.