U.S. European Command (EUCOM) views building partnerships as its highest theater priority. U.S. Air Forces in Europe (USAFE) seeks to build partnerships and partner capacity in the EUCOM area of responsibility. In spite of the potential benefits of USAFE's building-partnership (BP) activities, USAFE's posture and its BP activities do come with a cost. In today's austere fiscal environment, it is appropriate to assess how the United States and the U.S. Air Force (USAF) can build partnerships most efficiently while ensuring that the requirements for maintaining key alliances and partnerships continue to be met. This report characterizes the current policy debate on security cooperation and force posture in Europe through a review of the literature and discussions with key policymakers and legislative officials in Washington, develops a framework to describe the current BP approach and environment for the USAF in Europe, defines several alternative postures for conducting BP activities using a building-block approach to cost out each high-payoff BP activity, and recommends efficiencies to improve the USAF's BP activities in Europe.