The U.S. Army perceives a gap between its current light and heavy forces: light forces deploy rapidly, but lack staying power; heavy forces have immense power, but take too long to deploy. To close this gap and also to experiment with new tactics, General Eric Shinseki, the Army Chief of Staff, has begun a transformation process that will field medium-weight brigade combat teams beginning in 2003. The Army goal is to make these brigades light enough to deploy anywhere in the world in 4 days. Initially, these brigades will supplement the light and heavy forces. Over the next 20 to 30 years, the Army envisions the entire force becoming medium weight, with the ability to deploy by air anywhere in the world. To better understand the requirement for strategic responsiveness, as well as what is achievable, this study sought to answer the following questions: Can the Air Force meet the Army's 4-day deployment goal? What combination of deployment and basing options would maximize the strategic responsiveness of new Army forces? How much unambiguous warning does the United States usually have before it initiates military operations? How much of this time will civilian decisionmakers typically consume in their deliberations before ordering deployment of military forces? Are large U.S. forces likely to deploy globally or just to certain regions? At what depths from the littoral might U.S. forces have to operate? To assess deployment and basing options, the study team developed a simple spreadsheet that calculated transit times, loading and unloading times, and airfield throughput. It used military planning factors to determine aircraft usage rates, and maximum loads and ranges, and it drew on a variety of historical materials and interviews for the broader analysis of strategic responsiveness. This report concludes that the Stryker Brigade cannot deploy by air or sea from bases in the United States to key regions in 4 days. Deployment times range from 9 days (Colombia) to 21 days (Afghanistan). Even if unlimited numbers of aircraft were available, airlift would still be constrained by the condition of receiving airfields in most scenarios. In some scenarios, the brigade would close as rapidly with sealift but still fall well short of the 4-day goal. However, using combinations of airlift and fast sealift to move forces from forward bases or preposition sites, forces could reach key regions in 5 to 9 days and most of the globe could be covered in two weeks — a great improvement over historic deployment times for motorized forces. This study should be of interest to airmen and soldiers serving in plans, operational, analytic, and R&D organizations, as well as to the broader defense community.