Strategies of Ambiguity: Modeling Rhetoric in Primary Election Campaigns 1 Tom Hayes, Chad Murphy, Martin Johnson, and Shaun Bowler Department of Political Science University of California, Riverside Abstract When politicians do not state clear policy positions, key steps in the process of democratic representation – accountability, responsibility and the idea of a mandate – are drawn into question. The strategic incentives for candidates to adopt ambiguous positions are, therefore, of wide normative importance. However, the limited empirical research in this area focuses on voter perceptions rather than the actual messages of the candidates. We test expectations that candidates’ semantic ambiguity will vary with their chance of winning the nomination, ideological extremity, and the campaign calendar. We test these hypotheses using a measure of ambiguity derived from a high-dimensional computational model of concept representation, the Hyperspace Analogue to Language (Lund & Burgess, 1996a). We collected textual data from presidential candidate websites in four waves between June 2007 and February 2008. We find little support for expectations informed by the current theoretical literature, but do find that Democratic presidential candidates discuss policy with more ambiguity than the Republican field. Investigating the roots of this difference, we find that Democratic voters are both more risk-acceptant and more ideologically diverse than Republican voters. Consequently, candidates in the major parties appear to be responding strategically to the characteristics of their voters during the primary season. 1 Paper prepared for presentation at the Southwestern Political Science Association annual meeting, Las Vegas, Nevada, March 12-15, 2008, and Western Political Science Association annual meeting, San Diego, California, March 20-22, 2008. The authors thank Curt Burgess for continued collaboration and advice and Bob Hinh for assistance with data collection. Please direct correspondence to Martin Johnson, Department of Political Science, University of California, Riverside, CA 92521, (951) 827-4612, martin.johnson@ucr.edu .