The study also modeled the en-route airbases needed to support the movement of forces and equipment. The study did not model any scenarios without forward-deployed U.S. troops and equipment in Europe. Forward Presence Components Affect Mobility Requirements to Varying Degrees

A U.S. forward presence in Europe reduces mobility requirements, mobility costs, war-fighting risk, and time required for deployment to operations in Europe or Southwest Asia. Central Command officials have told us that the U.S presence in Europe, particularly the en-route system of airbases and the Air Force assets, would be critical to the success of their operations in Southwest Asia.European Command officials also told us that the U.S. presence allows the Commander to manage the missions assigned to the Command more easily, such as the small-scale contingencies in Bosnia and Kosovo. DOD officials suggested a relative ranking of U.S. military presence in Europe starting with the en- route system of airbases as having the greatest impact on mobility, followed by prepositioned equipment, Air Force aircraft and personnel, and finally Army combat forces. Air Force aircraft deployed in Europe allow forces to move more quickly to small-scale contingencies and reduce the burden on airlift and sealift. Also, European-based units deploy to Bosnia and Kosovo primarily by rail and road transportation, and are therefore less costly to move than forces requiring air transportation.
What GAO Found

The United States maintains 100,000 military personnel in Europe to provide rapid response in the event of a military crisis and help shape the international environment. These forward-deployed forces and equipment also facilitate the movement of U.S. forces to an area of operations. DOD has not quantified the impact of a forward presence in Europe on mobility requirements. However, Defense officials believe that, without forward-deployed forces and equipment in Europe, mobility requirements and costs would be considerably higher and deployment times longer, increasing war-fighting risk. The U.S. en-route system of airbases is critical to operations in Europe and Southwest Asia. U.S. prepositioned weapons and equipment in Europe facilitate military operations in nearby areas. Air Force aircraft and personnel deployed in Europe allow forces to move more quickly to small-scale contingencies in the area and reduce the airlift and sealift burden on U.S.-based units. As with the Air Force, Army combat and support units stationed in Europe allow forces to move more quickly and at less cost to small-scale contingencies in the area.