A considerable body of evidence on security cooperation illuminates the obstacles to burden sharing and strategies to elicit partner contributions. However, the implications for practice—how to integrate these insights into the design and implementation of security cooperation activities—remain underdeveloped. This disconnect between theory and practice is most evident in two areas. First, while practitioners now widely accept that it is essential to understand partners to influence their behavior, it remains unclear which characteristics they must account for, how to operationalize them, and the implications for tailoring security cooperation activities in response. Second, because numerous parts of the U.S. government control security cooperation decision-making, it is difficult for practitioners to coordinate and for partners to predict sustained engagement. How can practitioners design engagements to influence partners despite coordination challenges, and how can they align activities to achieve coherent outcomes?