This paper contributes to theory development about the politics of overlapping organizations. It explains how organizational overlap can affect the execution of organizational mandates. Within the universe of intergovernmental overlapping organizations, I argue that we need to study institutional positions in conjunction with governmental preferences. Based on these two variables, member-states have different strategies at their disposal: hostage-taking, forum-shopping, and brokering. These strategies affect the formulation and implementation of multilateral commitments. Taking the EU-NATO overlap as an example, I show how these strategies can lead to compromised organizational mandates, where hostage-taking leads to long delays in sending troops, operational uncertainties and wasted resources and brokers are left with innovating informal solutions.