How much military power does the United States need for its national security? Should it amass as much as it can to address emerging challenges and meet longstanding commitments? Or is the pursuit of superiority unnecessary and unachievable? These questions lie at the heart of current debates over U.S. grand strategy, military strategy, and defense investments. And they are increasingly relevant now that the dominance the United States once enjoyed is in decline. The Trump administration’s National Security Strategy, National Defense Strategy, and Nuclear Posture Review all acknowledge that adversaries have narrowed Washington’s lead in some areas and developed countermeasures in others. These documents also express the United States’ determination to arrest this erosion of power and develop new advantages if possible, ensuring, as senior officials often put it, that no soldier, sailor, airman, or marine will ever find him or herself in a “fair fight.” But what will it take for the United States to recapture a large military lead over competitors, and how feasible is that goal? Three schools of thought answer these questions differently, based on the value they attach to U.S. military superiority and the barriers they identify to restoring it. Existing approaches overlook several unique challenges to gaining and maintaining superiority in the current security environment, however, and underemphasize a number of key factors that could determine whether the United States achieves the goal it has set for itself.