Evaluating NATO enlargement: scholarly debates, policy implications, and roads not taken

NATO’s enlargement into Central and Eastern Europe after the Cold War is the subject of signifcant debate in academic and policy circles. With few exceptions, however, this debate focuses on single issues, such as whether enlargement led to the decline of the West’s relations with Russia. In this framing document, we look to expand the debate. We do so by sequentially reviewing the process by which NATO enlarged, outlining the array of issue areas within which to assess the consequences of NATO enlargement, and highlighting the particular importance of counterfactual analysis to any judgment of enlargement’s legacy. Building on a May 2019 workshop at Boston University, we also summarize the results of several articles that collectively evaluate the consequence of expansion for the USA, Russia, non-US NATO members, and the organization itself. Finally, we conclude by outlining elements of a broader research program on the afterefects of NATO enlargement.