Minimalist International Interventions

For the Future U.S. Overseas Presence, Access Agreements Are Key

By Stacie L. Pettyjohn

Stacie Pettyjohn is a political scientist at the RAND Corporation.

Fiscal, political, and strategic factors argue for a lighter U.S. footprint overseas. A shrinking defense budget, host-nation opposition to a U.S. military presence, and the increasing vulnerability of many overseas bases are endangering the sustainability of today's U.S. forward military presence. In the coming years, it is likely that these factors will force the Pentagon to make difficult decisions, which could include divesting some legacy bases or establishing new facilities.

But these decisions could have their virtues. Access agreements are less expensive to maintain than military bases, but they still enable the United States to scale its presence up or down, depending on the circumstances. A smaller and more sporadic U.S. military presence is less likely to cause friction with local populations. Host nations are likelier to grant Washington the right to use bases occasionally than to allow it to station forces on their territories permanently, so long as they can be convinced or believe that a smaller or more intermittent military presence remains a credible deterrent to aggression.

A focus on acquiring limited access would improve the probability that the United States could begin to make inroads in critical regions where it currently has little to no presence. Periodic access to host-nation facilities would also minimize the risk of making major investments in infrastructure only to have the host nation revoke U.S. rights. Finally, the United States would raise its chances of securing forward access for any given operation by diversifying its overseas presence. For these reasons, the Pentagon should adopt a posture that is less costly, less vulnerable, and less conspicuous — yet more versatile.

Transition Points

Over the past two centuries, the United States repeatedly adjusted its military posture in response to new threats, technological innovations, and the availability of overseas bases. Since independence, senior officials have developed and at least partially implemented seven distinct U.S. global postures: continental defense (1783–1815), continental defense and commercialism (1815–1898), oceanic posture and surge deployments (1906–1938), hemispheric defense (1938–1941), perimeter defense in depth (1943–1949), consolidated defense in depth (1950–1989), and expeditionary defense in depth (1990–present).

Until the drawdowns precipitated by the end of the Cold War, there had been a mostly consistent and linear development toward an increasing military presence overseas. However, there has also been a cyclical pattern of concentration and dispersion. On the one hand, when officials were confident in the identity and location of serious threats, they tasked forces with defending fixed locations. On the other hand, when it was unclear what types of threats might emerge or where they might be located, large portions of the military were organized, trained, and equipped as an expeditionary force that could be deployed abroad in response to emergent threats.

Access agreements are less expensive to maintain than military bases.

The permanent overseas military bases that remain today at the heart of America's global posture are a historical anomaly. The United States gained access and deployed its forces (and often their families as well) to large foreign bases only after World War II, to contain the Soviet Union. The sprawling garrisons in Western Europe and Northeast Asia that house U.S. troops and their dependents are a legacy of the Cold War, specifically the unique situation in the early 1950s, when the global threat of the Soviet Union drove many non-Communist states together, uniting them against a shared enemy.

Moreover, because World War II had debilitated many of these nations, they required external assistance to counter the Communist bloc, and the United States was the only nation capable of providing assistance. After the Korean War, the fear of Communism impelled the weakened Asian and European nations not only to align with the United States but also to allow Washington to position U.S. troops and their families on their territories indefinitely in large bases. The conditions that gave rise to these bases, however, are unlikely to be replicated in the near future.

A New Era Awaits

The Cold War experience does underscore one pertinent historical lesson. Throughout U.S. history, the most common reason that another nation has permitted the United States to establish a military presence on its territory is a shared perception of threat. Absent a serious danger to their security, nations are unlikely to voluntarily circumscribe their sovereignty by either providing U.S. forces temporary access to military facilities on their territories or allowing the United States to permanently station its forces within their borders. In other words, a period of shared threat is the most opportune time for the United States to forge new access agreements with prospective security partners.

Today, there is a lack of consensus in the United States and abroad regarding the likely consequence of China's economic growth and military modernization. Nevertheless, the United States has been able to exploit China's increasingly assertive behavior to expand America's rotational military presence in Australia and Singapore. If U.S. policymakers continue to regard an overseas military presence as essential, they would benefit from seizing on opportune moments when shared perceptions of threats are rising.

America's global defense posture remains one of the underlying elements of U.S. grand strategy, enabling the United States to reassure allies under duress, deter adversaries, project force abroad when called on to do so, and guarantee the freedom of the commons. Yet it is not clear that America's current overseas military presence is optimized for the future. The changes currently under way in the fiscal, political, and strategic environments could require significant revisions to the disposition and orientation of U.S. forces overseas. While the United States should retain legacy bases that remain useful for countering future security challenges, it should increasingly focus on developing access agreements instead of permanent garrisons. In light of the changes currently under way, it is also important to recall that the United States has repeatedly modified its global posture in response to new conditions. square