Nuclear status is typically treated as a stable feature of a state's capacity to possess, use, or build nuclear weapons. Challenging this view, After Fission reveals how states contest their nuclear status in the atomic age. By examining the legal structure of the Non-Proliferation Treaty, technical ambiguities surrounding nuclear testing, and debates over rights and responsibilities in the global nuclear regime, Sidra Hamidi argues that a state's nuclear status is not simply a function of technical capability. Instead, states actively contest the way they want their nuclear status to be presented to the world, and powerful states like the US, either recognize or reject these formulations. By analysing key diplomatic junctures in Indian, Israeli, Iranian, and North Korean nuclear history, this book presents a theory of when and how states contest their nuclear status which has key policy implications for negotiating with ostensible "rogues" such as Iran and North Korea.