This chapter reformulates the assumptions of securitization in a form appropriate to empirical studies and to the development of a comprehensive theory. Drawing on a variety of IR theories-constructivism, poststructuralism, critical theory-students of securitization aim to explicate the structures and processes that constitute security problems.1 Securitization theory elaborates the insight that no issue is essentially a menace. Something becomes a security problem through discursive politics.2 However, within securitization theory there are various ways to characterize this insight. On one side, those working in a poststructuralist tradition believe in a “social magic” power of language, a magic in which the conditions of possibility of threats are internal to the act of saying “security.” ‘The word “security”,’ argues Wæver (1995: 55), a pioneer of securitization studies, ‘is the act . . . by saying it something is done.’ In short, ‘security is a speech act’ (Ibid.).3 In essence, the basic idea of the speech act theory is, simply expressed: certain statements, according to Austin, do more than merely describe a given reality and, as such, cannot be judged as false or true. Instead these utterances realize a specific action; they “do” things: they are “performatives” as opposed to “constatives” that simply report states of affairs and are thus subject to truth and falsity tests. This view, which is part of the philosophy of language fold, provides foundations for the Copenhagen School (CS) approach to securitization. Thus, I call it “philosophical.”4