Most of the world’s governments advocate some form of nuclear disarmament, although they are far from achieving a nuclear-weapon-free world. Advocates of nuclear disarmament—be they individuals or States—vary in their identities, visions, motivations and practical agendas. The reasons they articulate for nuclear disarmament also vary. In this discussion paper, as part of UNIDIR’s Disarmament, Deterrence and Arms Control Dialogue, George Perkovich outlines who disarmers are, what kinds of goal they seek, common reasons for advocating nuclear disarmament, as well as critiques and possible failure modes. This, and his subsequent treatment of the relationship between disarmament, deterrence and arms control form the backdrop for brief responses from a range of informed commentators.