The United States conducts a wide range of security cooperation missions and initiatives that can serve as key enablers of U.S. foreign policy efforts to assist and influence other countries. For a relatively small investment, security cooperation programs can play an important role by shaping the security environment and laying the groundwork for future stability operations with allies and partners. Security cooperation, in the form of noncombat military-to-military activities, includes "normal" peacetime activities, such as building the long-term institutional and operational capabilities and capacity of key partners and allies, establishing and deepening relationships between the United States and partner militaries, and securing access to critical areas overseas. Security cooperation also can include conducting quasi-operational efforts, such as helping U.S. partners and allies manage their own internal defense. However, current national security challenges both create significant demands for U.S. security cooperation programs and deplete the resources needed to carry out these missions. The wars in Iraq and Afghanistan are occupying the regular, reserve, National Guard, and Special Forces trainers and advisors who would normally be called on to train and advise military counterparts. Furthermore, U.S. allies, who often complement the efforts of U.S. advisors and trainers, are also stretched thin by their own deployments to Iraq and Afghanistan. In an effort to find ways to improve security cooperation planning, coordination, and execution, the U.S. Army's Office of the Deputy Chief of Staff for Operations and Plans asked RAND Arroyo Center to conduct an assessment of key facets of U.S. security cooperation -- specifically, the missions, capabilities, and structure needed in the security assistance organizations (SAOs) that coordinate the military aspects of U.S. foreign relations, including security cooperation activities, at U.S. Missions around the world.