State failure poses one of the greatest threats to international peace and security. The collapse of governing institutions breeds civil wars, generates refugee flows, causes enormous civilian suffering, foments instability in neighboring countries, and provides safe havens for transnational criminal and terrorist organizations. As a result, commentators and policymakers have increasingly called for a remedy to the problem of state failure. One of the most compelling arguments is to draw on an old legal institution: international trusteeship by the United Nations (U.N.). This Article argues that while trusteeship may prove effective in managing state failure, it also carries risks. International interventions typically take limited control of the domestic environment of weak countries without absorbing their sovereignty. Trusteeship, in contrast, vests enormous authority and discretion in temporary international administrators, who in turn tend to centralize their power and decision-making in order to meet challenging mission mandates under difficult conditions. This “authority creep” absorbs sovereignty and in the process risks eroding incentives for leaders of failing states to cooperate with the U.N. Worse, unmitigated authority creep may weaken the political basis for successive international administration and reconstruction efforts. This Article concludes by outlining an alternative system of oversight for U.N. transitional administrators as a means of preserving partial sovereign authority and control for domestic political actors.