Party Politics, Ahead of Print.
Citizens’ ability to influence public decisions is the hallmark of democracy, and central to this are candidate selection mechanisms. Despite the increasing popularity of primaries across the globe, scholars disagree on how incumbency status shapes primary election contests. To address this question, I exploit an electoral reform in Argentina that forces parties and coalitions to participate in primaries, but allows these to be contested or uncontested. Employing an original data set on federal legislative nominations between 2011 and 2017, I show that internal divisions encourage contested primaries within the opposition, to which district-level rivals strategically respond in kind by fielding multiple internal lists to counter any potential electoral “bonus” others may enjoy from contesting in primaries. Combined with the influence of presidents and governors over selection procedures, these patterns entail that primary races are closely fought within the opposition but trouble-free under incumbency status.