The enlargement of NATO: The theory and politics of alliance expansion

Abstract

Most studies of alliance behavior operate under realist assumptions, which maintain that the presence of an external threat and an understanding of state's national security interests are the most important factors in explaining alliance membership. While security concerns continue to provide some insight on NATO's recent enlargement, this article contends that realism does not capture the full dynamics of expansion. NATO's ability to enlarge occurred due to a complex interplay of political factors. The United States’ leadership within the alliance, coupled with very favorable domestic conditions in the United States and effective lobbying efforts by Visegrad states provide a more complete understanding of how NATO was able to add new members. The presence and importance of these political factors and their interplay demonstrate that the dominant paradigm of realism offers only a partial explanation for NATO's expansion.