Previous research on the Bush Doctrine has tended to largely focus on its contents, more or less automatically assuming 9/11 to be the sole factor for the doctrine coming into existence. This article argues, on the contrary, that such a focus gives us an insufficient understanding of U.S. foreign policy since it underproblematizes how a doctrine comes into existence and why it takes a particular form. Instead, this article analyzes the political and societal discourses that are inextricably interlinked to doctrines, exploring how actors’ views both are reflections of discourses and also serve to reinforce them. Focusing on specific discursive mechanisms—securitization process, settled norms, and identity constructions—facilitates the explanation of both the origins of a doctrine and its contents. This article analyzes the discourses of the 3-month time period preceding the Bush and the Truman Doctrines. Comparing the Bush Doctrine with the Truman Doctrine, this article finds that the discourses of these two cases are very similar. In both cases the same central mechanisms are prominent, constructing a certain discursive linkage between the two. Finally, this article argues that a constructivist approach that employs a structured design is able to present more persuasive arguments than the traditional inductive-style narrative favored by many constructivist studies.