Intelligence sharing among countries with different technical capabilities and local knowledge is particularly valuable for countering terrorism, transnational organized crime, and the proliferation of weapons of mass destruction. States participating in intelligence-sharing arrangements must balance the benefits of more and better intelligence against the possibility that their partners will withhold or distort the information they share or will pass along to others the information they receive. Participants can balance these benefits and risks by introducing elements of hierarchy into their sharing agreements. Hierarchical arrangements allow a state to monitor more effectively for defection and to reassure others of its own commitments to the terms of their sharing arrangement. I evaluate this argument by analyzing intelligence sharing between the United States and Britain and West Germany during the early cold war, and conclude with some insights the approach sheds on contemporary sharing arrangements and problems.