Existing research in International Relations and Communications Studies on the role of rhetoric in foreign policy provides no satisfactory explanation for (1) why some Presidential justification campaigns for war are more coherent than others; (2) why some Presidents are more adept at engaging multiple audiences in their pro-war rhetoric than others? In answering these questions, this Doctoral project investigates how the institutional dynamics of the White House speechwriting process influence the construction and diffusion of U.S. Presidential rhetoric in three war-decision justification campaigns: the Korean War (25th June 1950- 29th September 1950), the Cambodian Intervention (15th April 1970- 22nd July 1970) and the Gulf Conflict (30th October 1990- 11th March 1991). The study uses a two-pronged methodology based on a discourse analysis of Presidential speeches and a process tracing of speechwriting patterns. The analysis of the chosen case studies demonstrates the explanatory value of an ideal typology of three speechmaking systems, which traces the influence of drafting integration on framing coherence and that of speech vetting on multi-audience engagement. The informal narrow vetting within fragmented drafting system is conducive to a disjointed justification campaign, overly targeted at one macro audience. The informal, wide vetting within integrated drafting type enables the President to construct coherent rhetoric focused on several macro audiences. The institutionalised vetting within integrated drafting model facilitates a coherent framing effort that engages multiple audiences.