Who shall have the power to define international terrorism? To answer this question, which means determining the international public enemy, is an eminently political task. According to Carl Schmitt, politics is essentially about determining the public enemy. When it comes to a situation of emergency, whoever is in the position to distinguish friend from enemy holds ultimate power. While Schmitt was still thinking primarily in terms of the nation-state, the determination of the public enemy has now become an international issue. To demonstrate this point, this article examines the political struggle behind the legal debate on the definition of international terrorism. This is done by comparing two debates on international terrorism, one held in the 1970s and the other in the 2000s. Both these debates had, and still have, their institutional locus in the UN General Assembly and its Legal Committee. In the 1970s the non-aligned countries tried to challenge the discretion of the West in determining the international public enemy. In the 2000s the incumbent regimes of the Third World agree with Western states that terrorism is a common threat. The main cleavage is now between the leading Western powers that would like to determine the public enemy on a case-by-case basis (the United States and the United Kingdom), and the status quo states that would like to tie these hegemonic powers by a legal definition. It is precisely the absence of such a legal definition that makes it possible for the hegemonic powers and their followers to determine the international public enemy on a case-by-case basis. A legal definition would increase the coherence of the international coalition against terrorism and serve as a limitation on the discretionary power of the hegemonic states.