Today, we are on the verge of a world without nuclear restraint. In the absence of formal arms control, how do we proceed? What broad principles and norms would we want? What measures might nuclear-armed states take, even without formal agreement, that would reduce the risk of nuclear war and control the arms race? I suggest that nuclear-armed states move toward a global regime of nuclear restraint and responsibility. Restraint would primarily take the form of reciprocal commitments and unilateral measures to avoid an arms race and reduce nuclear dangers. Responsibility refers to the fact that nuclear-armed states must pursue limited forms of deterrence and are accountable to the international community. I suggest several steps that governments, with the help of civil society, could take, beginning with the most minimal, declaratory initiatives and unilateral measures, and proceeding to steps that require more action.