Intervention comprises one of the most contentious issues in International Relations. This controversy results from the way normative understanding is structured around two key, but mutually exclusive, taboos: the moral expectation to respond in cases of humanitarian need and the protection of state sovereignty. In examining this dilemma, this article asks: what happens to the construction of rhetorical strategy, where that strategy seeks to justify intervention (or not), within a binary normative environment? It is argued that actors can only successfully construct a rhetorical case by engaging in, what is termed here, normative invalidation. In a binary situation, actors cannot adhere to both taboos. These taboos are so compelling, however, that actors must necessarily invalidate or neutralise any taboo not adhered to. This is discussed in relation to the Strategic Narratives paradigm and comparative case studies on the presidential rhetoric of Bill Clinton and Barack Obama.