In light of the significant changes in the international security environment resulting from the dissolution of the Soviet Union and declining resources available for defense needs, the Department of Defense (DOD) has been reexamining U.S. defense strategy, force levels, and budgetary requirements for the post-Cold War era. In 1990, the President presented a defense plan reflecting a shift in U.S. strategy from preparing for a global war in Europe against the Soviet Union to preparing for major regional conflicts against uncertain adversaries. This plan proposed a significantly reduced force structure, or base force, but retained sufficient forces to counter a possible reemergence of the Soviet threat. Following the change in administrations in 1993, the new Secretary of Defense reassessed U.S. defense requirements in an effort referred to as DOD’s bottom-up review. This review, completed in October 1993, examined the nation’s defense strategy, force structure, modernization, infrastructure, foundations, and resources needed for the post-Cold War era. As a result of the bottom-up review, DOD continued to focus U.S. strategy on regional threats; however, it de-emphasized the possibility of a reemerging Soviet threat and reduced U.S. forces to levels smaller than the base force. According to DOD officials, the Secretary of Defense called for the bottom-up review to be completed in time to be considered in developing DOD’s fiscal year 1995 budget and Future Years Defense Program. Therefore, the review was completed in about 7 months. In the Report on the Bottom-Up Review, DOD stated that much more work had to be done. According to DOD’s bottom-up review, the United States must pursue an overall defense strategy characterized by continued political, economic, and military engagement internationally. This strategy of engagement advocates (1) preventing the emergence of threats to U.S. interests by promoting democracy, economic growth, free markets, human dignity, and the peaceful resolution of conflict and (2) pursuing international partnerships for freedom, prosperity, and peace. The bottom-up review outlined the new dangers facing U.S. interests in the post-Cold War era and a specific strategy for dealing with each one. These dangers included (1) the proliferation of nuclear weapons and other weapons of mass destruction; (2) regional dangers, posed primarily by the threat of large-scale aggression by major regional powers with opposing interests; (3) dangers to democracy and reform in the former Soviet Union, Eastern Europe, and elsewhere; and (4) economic dangers to national security. In the Report on the Bottom-Up Review, the Secretary of Defense cited regional aggression as chief among the new dangers. To deal with regional aggression and other regional dangers, DOD’s strategy is to (1) defeat aggressors in major regional conflicts; (2) maintain a presence overseas—the need for U.S. forces to conduct normal peacetime operations in critical regions—to deter conflicts and provide regional stability; and (3) conduct smaller-scale intervention operations, such as peacekeeping, humanitarian assistance, and disaster relief. To deal with the threat of regional aggression, DOD judged that it is prudent for the United States to maintain sufficient military power to be able to fight and win two major regional conflicts that occur nearly simultaneously. The bottom-up review determined the specific forces, capabilities, and improvements in capabilities for executing the two-conflict strategy. In reaching its conclusions, DOD examined various strategy and force options for major regional conflicts, as shown in table 1.1. For assessment purposes, DOD focused on two specific scenarios involving regional aggression. In evaluating the strategy and force options, DOD also considered requirements for conducting (1) peace enforcement or intervention operations in smaller-scale conflicts or crises, (2) overseas presence, and (3) deterrence of attacks with weapons of mass destruction. DOD, for various reasons, chose the strategy of fighting and winning two nearly simultaneous major regional conflicts and related forces with enhancements—the third option shown in table 1.1. For example, DOD believed that this option would possibly deter a second regional aggressor from attacking its neighbors while the United States was responding to another regional conflict. In addition, fielding forces sufficient to win two wars nearly simultaneously would provide a hedge against the possibility that a future adversary might one day confront the United States with a larger-than-expected threat. Finally, DOD believed that this strategy option, forces, and enhancements were affordable within expected budget constraints. According to its Report on the Bottom-Up Review, DOD also estimated the cost of the bottom-up review program and matched it against the President’s objective for reducing the defense budget. DOD estimated that the program would achieve $91 billion in total savings and that additional savings would be identified during DOD’s normal program and budget review. DOD estimated that the projected force would be available by fiscal year 1999. DOD used the results of the bottom-up review to develop its fiscal year 1995 budget and Future Years Defense Program. In concluding that the forces selected for the third option could implement its strategy, DOD made several key assumptions about the forces’ deployability and capabilities, including that forces involved in other operations, such as peacekeeping, would be redeployed to a regional conflict; certain specialized units or unique assets would be shifted from one sufficient strategic lift assets and support forces would be available; Army National Guard enhanced combat brigades could be deployed within 90 days of being called to active duty to supplement active combat units; and a series of enhancements, such as improvements to strategic mobility and U.S. fire power, were critical to implementing the two-conflict strategy and would be available by about 2000. The specific enhancements included improving (1) strategic mobility, through more prepositioning and enhancements to airlift and sealift; (2) the strike capabilities of aircraft carriers; (3) the lethality of Army firepower; and (4) the ability of long-range bombers to deliver conventional precision-guided munitions. Completing these enhancements, according to DOD, would both reduce overall ground force requirements and increase the responsiveness and effectiveness of its power projection forces. In most cases, the projected enhancements involved ongoing programs to upgrade existing capabilities. For example, the bottom-up review cited the need for additional airlift and sealift assets to improve strategic mobility. DOD had previously identified this need in its 1991 mobility requirements study and had already programmed funds to procure some of the specific assets. According to the Secretary of Defense, the bottom-up review was a comprehensive reassessment that set the framework for defense planning for the next 5 years and beyond. In September 1993 and May 1994, the Secretary issued his defense planning guidance for fiscal years 1995 to 1999 and fiscal years 1996 to 2001, respectively. This guidance formally directed the military services and defense agencies to implement the bottom-up review’s conclusions. The May 1994 guidance included an illustrative planning scenario reflecting DOD’s concept of how the United States would respond to two major regional conflicts that occur nearly simultaneously. Among other things, the scenario detailed the amount of time between the outbreak of hostilities in both conflicts, number and types of forces deployed to each conflict, timing of deployments, and projected time for completing various combat phases. DOD directed military planners to use this scenario, along with other guidelines in the September and May guidance, in developing program and budget requirements for DOD’s selected strategy and forces. In considering DOD’s portion of the President’s budget for fiscal year 1995, Members of the Congress raised questions about the bottom-up review, including the accuracy of its assumptions and affordability of its projected force. As a result, in the Fiscal Year 1995 National Defense Authorization Act, the Congress is requiring the Secretary of Defense to review the assumptions and conclusions of the President’s budget, the bottom-up review, and the Future Years Defense Program. The Secretary is required to submit a report on the results of its review to the President and the Congress in May 1995. Among other things, this report must describe the force structure required to execute DOD’s two-conflict strategy in light of other ongoing or potential operations and may also address possible adjustments to the strategy. We examined DOD’s bottom-up review assumptions about key aspects of the two-conflict strategy to determine whether they reasonably supported DOD’s conclusion that the projected force, with enhancements, can execute the strategy. In conducting our assessment, we did not examine DOD’s rationale for selecting the two-conflict strategy, the capabilities of potential regional aggressors, and the extent to which allied support could reduce the need for U.S. forces. To determine DOD’s assumptions and conclusions about executing the two-conflict strategy, we interviewed knowledgeable officials involved in the bottom-up review at the offices of the Assistant Secretary of Defense for Strategy, Resources, and Requirements; the Assistant Secretary of Defense for Reserve Affairs; the Joint Chiefs of Staff; and the Army, Air Force, Navy, and Marine Corps headquarters. We also reviewed relevant documentation, including the final report on the bottom-up review and the Secretary of Defense’s planning guidance, and received briefings on regional dangers from DOD officials. We did not examine DOD’s rationale for selecting the two-conflict strategy; rather, we focused on examining DOD’s assumptions on key aspects of the strategy. DOD denied us access to specific information on the inputs and results of its analysis of force options. However, we obtained considerable information on DOD’s analysis through interviewing knowledgeable officials and reviewing available documentation.