After sixty-five years of pursuing a grand strategy of global leadership— nearly a third of which transpired without a peer great power rival—has the time come for the United States to switch to a strategy of retrenchment? According to most security studies scholars who write on the future of U.S. grand strategy, the answer is an unambiguous yes: they argue that the United States should curtail or eliminate its overseas military presence, abolish or dramatically reduce its global security commitments, and minimize or eschew efforts to foster and lead the liberal institutional order. Thus far, the arguments for retrenchment have gone largely unanswered by international relations scholars. An evaluation of these arguments requires a systematic analysis that directly assesses the core claim of retrenchment advocates that the current "deep engagement" grand strategy is not in the national interests of the United States. This analysis shows that advocates of retrenchment radically overestimate the costs of deep engagement and underestimate its benefits. We conclude that the fundamental choice to retain a grand strategy of deep engagement after the ColdWar is just what the preponderance of international relations scholarship would expect a rational, self-interested leading power in America's position to do.