Arms Control, once a keystone of American foreign policy, has fallen out of favor with many U.S. policymakers. Yet it is needed more than ever, although in a different from. Levi and O’Hanlon underscore that future arms control must have clear priorities and focus on proliferation of the most dangerous technologies to the most dangerous actors. It must also provide early warning of violations, partly to allow coercive action (and perhaps even military force) to be considered in the event of such violations. Rather than hold our the fanciful prospect of nuclear abolition as an incentive for non-nuclear states to forge nuclear weapons, it should offer security guarantees to a growing collective security community of democratic, peaceful states.