ABSTRACT
Structural realism contains a straightforward alliance theory. States balance rather than bandwagon; alliances form because weak states band together against great powers in order to survive in an anarchic international system. Alliance patterns change because the international distribution of power changes. Traditional alliance theory is firmly grounded in realist thinking. Realism, however, is indeterminate with regard to explaining the origins of, the interaction patterns in, and the endurance of NATO. Realism’s indeterminacy with regard to the origins of NATO also applies to interaction patterns within the Western Alliance. To begin with, structural realism of the Waltzian variety has a clear expectation regarding cooperation among allies. The indeterminacy of realism also applies when we start using the theory to predict the survivability of NATO after the Cold War. Structural realists in the Waltzian tradition should expect NATO to wither away with the end of the Cold War.
