The time is ripe to revisit questions about the future of the U.S. strategic posture. Next year, 2021, will bring a new defense strategy review and a return to basic questions of defense policy and posture by a new Congress and perhaps also a new administration. U.S. strategic forces, broadly defined here to include not just nuclear forces but also non-nuclear strategic strike, missile defense, and space and counter-space capabilities, can be expected to play a more prominent role in that process than in the past. This follows from the changing nature of modern warfare, the need to compete with and deter two major power adversaries who put a lot of stock in the strategic dimensions of modern war, and the need to address major concerns about U.S. deterrence strategy articulated in 2018 by the National Defense Strategy Commission. This volume examines the projected modernization of U.S. strategic forces between 2020 and 2030. It also explores whether they will be "fit for purpose" and the associated questions about what that future purpose might be. It includes also net assessments of strategic advantages gained or lost by 2030 from the perspectives of Washington, Moscow, and others.