......................................................................................................................................................................................................................................................................................................................... doi:10.1017/S1049096517002505 © American Political Science Association, 2018 PS • April 2018 351 Politics Primary Distrust: Political Distrust and Support for the Insurgent Candidacies of Donald Trump and Bernie Sanders in the 2016 Primary Joshua J. Dyck, University of Massachusetts Lowell Shanna Pearson-Merkowitz, University of Rhode Island Michael Coates, University of Maryland ABSTRACT Donald Trump dominated the 2016 Republican primary despite the fact that he was not, in any meaningful sense, a Republican. Bernie Sanders came just shy of winning the Democratic nomination despite the fact that he switched his party affiliation from Independent to Democrat only three months before the election. Why did two candidates with no formal ties to the political parties fare so well? One possibility is that primary vot- ers are more ideologically extreme and that ideology drives support for these candidates. However, another possibility is that concerns about government process drives support for insurgent candidates. We test the proposition that distrust was the primary motivator of primary voting for these two insurgent candidates using two datasets: a poll of New Hampshire voters fielded a week before their primary and a national poll taken in June 2016. Results confirm the hypothesis that distrust drove intraparty vote choice in the 2016 presidential primaries. G eneral elections can be predicted well in advance because most people decide how to vote using a com- bination of partisan attachment—typically acquired early in life—and reflection on the “nature of the times” (Campbell et al. 1960). As Achen and Bartels (2016, 267) argued, “The primary sources of partisan loyalties and voting behavior…are social identities, group attachments and myopic retro- spections, not policy preferences or ideological principles.” However, in congressional and presidential primaries, this process works differently. Voters choose between two or more candidates who all bear the same partisan label. Making distinctions among the minutia of policies in which these candidates disagree can be difficult, even for the most sophisticated voter. Most primary voters, therefore, must figure out who to support without the shortcuts provided by the partisan brand (Zaller 1992). Thus, an “insurgent” candidate occasionally comes along and unseats a well-known and possibly well-loved incumbent or the party’s presumptive nominee. In the 2016 election, the United States experienced insurgent candidacies in both party primaries from Donald Trump and Bernie Sanders. In other countries that have multiparty systems, both might have run under a different party label. However, in the United States, third parties face barriers to running for public office, particularly the presidency. Because the primaries are open to a public vote, would-be third-party candidates can run strategi- cally under major party labels. We consider Trump and Sanders as insurgent candidates because they were (1) only nominal members of the parties with which they ran but, more important, because (2) their candidacies were not welcomed by the party establishment. Sanders has held elective office since 1991 as an Independent. Although he has caucused with Democrats, he has always made clear to both his home state and the national media that he is not a member of the Joshua J. Dyck is associate professor in political science at the University of Massachusetts Lowell. He can be reached at joshua_dyck@uml.edu. Shanna Pearson-Merkowitz is associate professor in political science at the University of Rhode Island. She can be reached at shanna_pearson@uri.edu. Michael Coates is a doctoral candidate in government and politics at the University of Maryland, College Park. He can be reached at azhain@umd.edu.