The United States emerged as the world’s sole superpower from the embers of the Cold War’s end, without, however, a wholesale reformulation of the principles and tools used to execute US grand strategy. This was particularly true in Europe, where the United States remained engaged politically, economically, and military; retained significant numbers of forward-deployed forces; and orchestrated the continuation and eventual expansion of NATO. For the United States, and for many Europeans, continued American dominance after 1991 of the continent’s security through NATO was a logical outgrowth of what Washington had provided in the West after 1945. Even within the context of America’s leadership of NATO, alternative strategies to the ultimate path of NATO’s post-1999 enlargement were possible. These included the Partnership for Peace, initially seen as an alternative to NATO enlargement formulated by the Pentagon; some enlargement of NATO to the east, but not as much as occurred; and a concrete path for Russia to join the alliance. This chapter considers the pros and cons of each of these alternatives to the NATO enlargement policy chosen by the United States and its partners in order to provide a more detailed assessment of the policy than has existed previously.

The Cold War’s denouement not only saw profound political changes throughout Eurasia, but an unprecedented power shift resulting from the Soviet Union’s decline that ultimately ushered in the United States’ “unipolar era.” Nevertheless, the United States’ response to the late Cold War power shift remains underexplored. This chapter fills the gap by examining the processes by which the United States recognized the power shift underway and adapted its foreign policy. I make three arguments. First, American policymakers in the Reagan and George H. W. Bush administrations acknowledged that Soviet decline rebounded to the United States’ geopolitical advantage. Second, American policymakers responded by exploiting Soviet problems, driven by recognition that Soviet decline allowed for American gains, yet worried that the window for gains would soon close. Third, this effort altered European security, as the United States undercut the Soviet Union as a challenger while fostering conditions that could allow it to dominate European security irrespective of whether Soviet problems continued. Put simply, the United States used the Soviet decline to reify American advantages in Europe, garnering oversight over a region that had long been the cockpit of geopolitical contestation. The result meant that unipolarity also translated into American near-hegemony in Europe.