VANGUARD, the Air National Guard's (ANG's) long-range transformation program (released in December 2002), calls for the ANG to evaluate new concepts, prepare for new missions, and adopt a new culture that capitalizes on ANG strengths and ensures that the ANG continues to add value as warfighters and to warfighters in the future. One way to support warfighting and warfighters is to continue to support the Air and Space Expeditionary Force (AEF), a concept developed by the Air Force to allow quick response, when appropriate, to national security interests with a tailored, sustainable force. The ANG already plays an important role in the AEF during wartime operations. Here, RAND looks at expanding that role both in peacetime and during operations. This monograph focuses on operational effects, such as the ability to configure support rapidly and the ability to deploy and employ quickly, enabling the evolving AEF mission. Specifically, this analysis concentrates on options for combat support and reachback missions in four Air Force mission areas: (1) Civil engineering deployment and sustainment capabilities, (2) Continental United States (CONUS) Centralized Intermediate Repair Facilities (CIRFs), (3) The Force Structure and Cost Estimating Tool -- A Planning Extension to GUARDIAN capabilities, and (4) Air and Space Operations Center (AOC) reachback missions. More specifically, this project evaluates how fundamentally different policies, at the unit level and above the unit level, are likely to affect Total Force capabilities in meeting the needs of the AEF mission. Through VANGUARD, the ANG has recognized the need to undertake a fundamental reexamination of its structure to ensure that it continues to play a leading role in meeting the AEF mission. After evaluating each of the four Air Force mission areas, the report investigates transformational opportunities for the ANG that would add the most value in achieving the desired operational effects.