During the 2008 presidential campaign, the question of mass participation in primaries and caucuses became unusually salient, with a close Democratic race calling special attention to these often overlooked procedural elements of America's democratic system. This study adds a new element to scholarship on institutional design and citizen participation by way of a survey-based experiment conducted in the midst of the 2008 campaign. The results show that institutional choices are not neutral. Nominating candidates through caucuses rather than primaries not only reduces the number of participants, but also significantly affects the ideological composition of the electorate. Caucuses produce a more ideologically consistent electorate than do primaries, because policy centrists appear to avoid caucuses. This experimental finding is strongly buttressed by the observational data on Obama and Clinton voters.
(Online publication September 30 2013)
* Brigham Young University (email: Chris_karpowitz@byu.edu). The authors wish to thank the anonymous reviewers and participants in both the faculty research seminar at Brigham Young University and the 2009 CCES Conference for valuable comments and suggestions on earlier versions of the manuscript. Replication data are available at http://dx.doi.org/doi:10.1017/S0007123413000288.