City diplomacy luminary and Attorney Michael Shuman, a leader of the former Center for Innovative Diplomacy, reminds us that local government participation in foreign affairs is enumerated in and protected by the Constitution. Thus, when American local governments responded to the threat of nuclear annihilation vis-à-vis the U.S. arms race with the Soviet Union, to the federal government’s inadequate response to Apartheid, and to other problems from the federal-level, the resultant municipal activism was not only legal, it was defining of American federalism.