America in the 1920s and 1930s is often characterized as having been isolationist in the realm of security policy. This article offers a critique of this characterization. American diplomacy in the 1920s was subtle but ambitious and effective. American policy in the years leading up to the bombing of Pearl Harbor was in fact quite responsive to events on the European continent. Isolationists did exist, of course, but they never came close to constituting a majority. In short, American isolationism is a myth.