Why does realist political advocacy for a more limited national security agenda fail? For nearly two decades, realists in general and Stephen Walt and John Mearsheimer in particular have publicly lamented an endemic problem of threat inflation in America, culminating in the unnecessary 2003 Iraq War. This article argues that understanding the failure of realist advocacy requires appreciating its roots in the model of the marketplace of ideas, an ironically liberal model of discourse that downplays questions of power. As a corrective, I argue that securitization theory and its framing of security debates as discursive, competitive and ultimately power-laden processes offers substantive insights into understanding realism’s anaemic interventions. Focusing specifically on the advocacy of Stephen Walt and John Mearsheimer in their opposition to the 2003 Iraq War, I examine how powerful processes involving social identity and collective emotion came to be turned against realists by their neoconservative interlocutors. In the final section, I suggest that a common research agenda among realism and securitization scholarship is needed to explore their joint interest in the statecraft of threat construction in order to produce practical, politically relevant knowledge.