This independent assessment is a comprehensive study of the strategic benefits, risks, and costs of U.S. military presence overseas. The report provides policymakers a way to evaluate the range of strategic benefits and costs that follow from revising the U.S. overseas military presence by characterizing how this presence contributes to assurance, deterrence, responsiveness, and security cooperation goals.

Section 347 of the 2012 National Defense Authorization Act called on the Department of Defense to commission an independent assessment of the overseas basing presence of U.S. military forces. As the recipient of that commission, RAND's National Defense Research Institute conducted an independent assessment of the advisability of changes in the overseas basing presence of U.S. forces based on an evaluation of strategic benefits, risks, and costs. The report characterizes how overseas presence contributes to assurance of allies, deterrence, contingency responsiveness, and security cooperation, along with the risks involved with investing in facilities overseas. It breaks new ground in the understanding of the costs associated with overseas presence, including how permanent and rotational presence costs compare, and provides cost models for policymakers to weigh alternative posture options. To support this understanding of costs the report also lays out the conditions of U.S. installations and levels of host nation support. The report concludes that there are certain minimum requirements necessary to carry out the current national security strategy, but it is prudent, based upon the net value produced, to maintain an overseas posture that goes beyond these minimums. Additionally, it combines benefit, cost, and risk considerations to distill a number of strategic judgments that have implications for the advisability of considering identified posture changes.

On August 16, 2004, the Bush Administration announced a proposal to significantly alter the U.S. overseas military basing posture. The proposal would, if implemented, establish new overseas operating sites, and transfer up to 70,000 U.S. troops, plus 100,000 family members and civilians, from Europe and Asia back to the United States. The Administration argues that current U.S. global basing arrangements are a product of World War II and the Korean War. With the end of the Cold War, these basing arrangements need to be updated to ensure that U.S. forces are optimally positioned to respond to potential 21st-Century military threats. The Administration's proposal has received mixed reactions from non-DoD observers. A May 2004 Congressional Budget Office report raises questions concerning the potential cost effectiveness of changing the current Army overseas basing posture. The Administration's proposal raises several potential oversight issues for Congress. This report will be updated as necessary.

In August 16, 2004, President Bush announced a program of sweeping changes to the numbers and locations of military basing facilities at overseas locations, now known as the Integrated Global Presence and Basing Strategy (IGPBS) or Global Posture Review, a component of ongoing force transformation efforts. Roughly 70,000 personnel would return from overseas locations from Europe and Asia to bases in the continental United States (CONUS). Other overseas forces would be redistributed within current host nations such as Germany and South Korea, and new bases would be established in nations of Eastern Europe, Central Asia, and Africa. In the Department of Defense's (DOD) view, these locations would be closer, and better able, to respond to potential trouble spots. In August 2005, the congressionally mandated Commission on the Review of Overseas Military Facility Structure of the United States (also known as the "Overseas Basing Commission") formally reported its findings. It disagreed with the "timing and synchronization" of the DOD overseas re-basing initiative, and questioned whether a strategic vision agreed upon by all effected government agencies was guiding the re-basing. It also saw the initiative as potentially at odds with stresses on the force that the operations in Iraq and Afghanistan caused. The Commission questioned whether sufficient interagency coordination, such as State Department led basing rights negotiations, have occurred. It expressed doubts that the military had enough airlift and sealift to make the strategy work, and noted that DOD had likely underestimated the cost of all aspects associated with the moves (DOD budgeted $4 billion, the Commission estimated $20 billion). The Commission also expressed fear that the re-basing could harm military quality of life, which would in turn hamper recruiting and retention. Recent international diplomatic and security developments could further influence debate on overseas basing.

As the U.S. military presence in the Middle East winds down, Asia and the Pacific are receiving increased attention from the American national security community. The Obama administration has announced a “rebalancing” of the U.S. military posture in the region, in reaction primarily to the startling improvement in Chinese air and naval capabilities over the last decade or so. This timely study sets out to assess the implications of this shift for the long-established U.S. military presence in Asia and the Pacific. This presence is anchored in a complex basing infrastructure that scholars—and Americans generally—too often take for granted. In remedying this state of affairs, this volume offers a detailed survey and analysis of this infrastructure, its history, the political complications it has frequently given rise to, and its recent and likely future evolution. American seapower requires a robust constellation of bases to support global power projection. Given the rise of China and the emergence of the Asia-Pacific as the center of global economic growth and strategic contention, nowhere is American basing access more important than in this region. Yet manifold political and military challenges, stemming not least of which from rapidly-improving Chinese long-range precision strike capabilities, complicate the future of American access and security here. This book addresses what will be needed to maintain the fundaments of U.S. seapower and force projection in the Asia-Pacific, and where the key trend lines are headed in that regard. This book demonstrates that U.S. Asia-Pacific basing and access is increasingly vital, yet increasingly vulnerable. It demands far more attention than the limited coverage it has received to date, and cannot be taken for granted. More must be done to preserve capabilities and access upon which American and allied security and prosperity depend.