Can contemporary arms control keep pace with the rapid rate of change in both geopolitics and technology? While the challenges to future arms control point to a rocky road ahead, measures that build confidence, reduce miscalculation, enhance transparency, restrain costly and dangerous military competition, and offer useful mechanisms and venues for addressing sources of conflict will be of increasing value. For arms control tools to succeed, however, they must be adapted to the current security environment, account for rapidly evolving technological and informational factors, and consider alternative structures, modalities, and participation models. Indeed, now is the time for a recoupling of arms control with deterrence in a way that recognizes these new realities. Now is the time for integrated arms control that enhances stability, embraces plurality, and reinforces resiliency. This CSIS study examines the implication and prospects for the future of arms control in a highly competitive security environment in which challenges from advanced technologies and diminished state control over processes of verification become increasingly prominent features, even as the scope and modalities of arms control grow more complex and multifaceted. The report offers a reexamination of the broad contours of arms control and its role in managing competitive security risks and challenges and the implications for U.S. policymakers, academics, and strategic thinkers engaged in U.S. nuclear policy.