From the moment Barack Obama entered the national political scene in 2004, his formidable rhetorical skills were a central component of his public persona and his political success. Not surprisingly, a growing body of research has examined Obama's rhetorical techniques. Thus far, however, these studies have consisted almost entirely of qualitative analyses of single speeches, making it difficult to generalize about the broader features of Obama's rhetorical approach and impossible to understand the determinants of his rhetorical choices. This study fills these gaps in the literature by systematically tracking Obama's rhetoric over the course of campaign 2008 and testing competing explanations for the variation that occurs during this period. Using a unique computer-assisted content analysis procedure that draws coding categories directly from the more than 11,500 distinct words that Obama used during his campaign, the authors analyze 183 speeches and debates from his announcement of candidacy in February 2007 to his victory speech in November 2008. Obama's campaign rhetoric varied by speaking context, geography, and poll position, indicating a twofold rhetorical approach of emphasizing policy and thematic appeals while downplaying more contentious issues.