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I’m a PhD candidate in political science at the Graduate School of North American Studies of the Freie Universität Berlin. My research interests include Congress, political parties, elections, intra-party factions, and candidate nomination systems. My PhD thesis examines intra-party factions in recent congressional primary competitions, considering their role in nominating experienced candidates and their contribution to trends of partisan polarization in Congress.


Intra-Party Factions & Inter-Party Polarization in U.S. Congressional Primaries: How Factional Nominations Influence Candidate Quality & Position

Dissertation in Political Science

First supervisor: Prof. Dr. Christian Lammert
Second supervisor: Prof. Dr. Sean M. Theriault
Third supervisor: Prof. Dr. Max Steinhardt

Interest in congressional primaries among academic and media sources has boomed in recent years, in large part due to an ongoing debate about whether these intra-party contests as a source of inter-party polarization in Congress. This thesis demonstrates changes in the dynamics of competition, offering evidence that between 2006 and 2020 congressional primaries became dominated by ideological differences between candidates proximate to competing factions, first in the Republican and then in the Democratic Party. I consider causes of this development and implications in terms of candidate quality and the selective and adaptive polarizing effects, empirical testing if modern primaries reward ideologically extreme and amateur candidates. Taking a contest-centered approach, the thesis foregrounds the dynamics of and reasons for primary competitions to better understand the implications for inter-party polarization. In doing so, the thesis demonstrates that trends of intra-party factionalism in the congressional nomination process influence partisan polarization.

The first section of the thesis documents the increasingly factional nature of congressional primary competition using an original dataset of all contested Democratic and Republican primaries for the US Congress between 2006 and 2020 (n = 3,332). I code candidates’ proximity to factional ideal-types to assess the nature of intra-party competition using a combination of established scaling methods (DW-NOMINATE and CFscores), endorsements, affiliations, and campaign positions. Following the existing literature, I also code reasons for contests, using candidate statements about their reasons for running for office. During the period of study, numbers of contested primaries increased in line with greater focus on ideological differences, with most races taking place between candidates proximate to competing factions by the end of the period. Understanding parties as networks, I demonstrate that factions now serve as important sub-party coalitions that candidates attempt to engage to earn the nomination. In 2006, most primaries candidates prioritized valence factors such as competence and experience in public office, by 2020, factional differences between candidates had become the main reason for nomination contests taking place. This transformation took place first in the Republican then the Democratic Party. Factions, previously regionally aligned, have nationalized, resulting in ideological intra-party diversity within congressional districts. Furthermore, as inter-party general elections have become dominated by partisanship and affect, policy discussions have moved into the intra-party sphere.

The second section of the thesis tests the consequences of factional primary competitions in terms of candidate quality and ideological position. Greater numbers of contested primaries and the reduced salience of valence factors in primary elections have correlated with fewer nominees having prior experience in elected office, or, in the terms set out by existing literature, should be considered ‘quality’ candidates. The presence of a primary may be beneficial to an amateur candidate, who may earn the nomination via a direct pitch to partisan supporters. When rates of primary competition were lower, party officials could directly nominate candidates with relevant experience. The change in the dynamics of primary competition have further benefitted inexperience candidates, when valence factors are more salient, quality candidates are more frequently nominated. In primaries focused on ideological difference and issue positions, prior experience is less salient, meaning fewer quality candidates are nominated.

Factional primary competition may also have consequences for congressional polarization. Congressional primaries are frequently cited as incentivizing extreme candidates, despite mixed empirical evidence underpinning the claim. I test whether (factional) primaries had a causal effect on candidate extremism in three ways: First, I evaluate whether nominees from (factional) primaries were more extreme than other nominees, and whether comparatively extreme candidates were more often nominated in (factional) primaries, understood here as the selective effect of primaries. Second, I test whether primaries caused candidates to take more extreme positions within an election cycle, as expected under the strategic positioning dilemma. To analyze the within-cycle adaptive effect, I use a unique scaling method to compute ideal points of primary candidates across the 2020 election cycle. Second, I test whether factional challenges to incumbents on ideological grounds caused members of Congress to adopt more extreme voting positions in Congress. These findings have important implications for our understanding of the role of intra-party factions in the candidate selection process. The thesis provides a deep analysis of competition in modern congressional primaries, including a large-scale qualitative assessment of intra-party dynamics in primary elections. These findings indicate that congressional primaries remain effective tools for selecting quality candidates, especially when compared with alternative methods of selection such as party conventions. Importantly, these findings highlight the need for a more nuanced understand of the role of primary elections than is widely portrayed both in media sources and the discipline of political science. The need for greater understanding of the dynamics of primaries appears particularly acute given that one of the main ways they affect candidate position is through adaption, with candidates likely influenced by narratives of primary electorates as extreme. Throughout the thesis, I consider the implications of findings for voters, parties, candidates, the institution of Congress, and the discipline of political science.


Peer-Reviewed Publications

Cowburn, Mike and Michael T. Oswald. 2020. ‘Legislator Adoption of the Fake News Label: Ideological Differences in Republican Representative Use on Twitter’. The Forum 18(3): 389–413.

Book Chapters

Cowburn, Mike. Forthcoming. “Experience Narratives and Populist Rhetoric in U.S. House Primaries” in Michael T. Oswald (ed.) The Palgrave Handbook of Populism. Palgrave Macmillan.

Cowburn, Mike. 2020. “The Transformation of the Congressional Primary” in Michael T. Oswald (ed.) Mobilization, Representation and Responsiveness in The American Democracy. Palgrave Macmillan.

Other Publications

Cowburn, Mike. 2020. “Not Just the Presidency: Congressional Primaries 2020.” Atlantische Akademie

Cowburn, Mike. 2020. “Fostering Engagement in Primaries and Caucuses.” PolticalScienceNow

Conference Papers

04/202179th Annual Midwest Political Science Association (MPSA)*
Paper: “Partisan Communication in Two-Stage Elections: The Effect of Primaries on Intra-Campaign Positional Shifts in Congressional Elections”
03/2021Political Studies Association Annual Conference*
Paper: “Inclusivity and Centralisation of Candidate Selectorates: Factional Consequences for Centre-Left Parties in Germany, England, and the United States”
01/202149th Annual Conference of the American Politics Group of the UK Political Studies Association*
Paper: “Legislator Adoption of the Fake News Label: Ideological Differences in Republican Representative Use on Twitter”
11/2020Annual Meeting of the Political Science Section of the German Association for American Studies*
Paper: “Republican Legislator Adoption of the Fake News Label”
09/2020Annual Meeting of the American Political Science Association*
Paper: “Ideological Difference & Party Destabilization in Congressional Primary Contests”
08/2020European Consortium for Political Research General Conference*
Paper: “Intra-Party Ideological Disagreement in Congressional Nomination Processes”
07/2020Early Career Network Annual Conference of the Political Studies Association*
Paper: “The Rise of Ideology in U.S. Congressional Primaries”
06/2020Annual Conference of the European Political Science Association*
Paper: “Ideological Competition in U.S. Congressional Primaries”
06/2020Annual Conference of the German Association for American Studies~
Paper: “Polarizing Primaries? Income Inequality & Congressional Candidate Selection”
04/202078thAnnual Midwest Political Science Association Conference~
Paper: “From Personal to Ideological: The Transformation of the Congressional Primary”
Paper: “The Evolution of the Fake News Label: Ideology & Time in Congress as Determinants of Republican Representative Use on Twitter”
12/2019British Association for American Studies Postgraduate Conference, British Library
Paper: “Communication in Congressional Primaries: The Rise of Ideology in Intra-Party Contests”
11/2019Annual Meeting of the Political Science Section of the German Association for American Studies, Heidelberg University
Paper: “Democratic Re-Engagement? The Ideological Foundations of Growing Primary Participation”
06/2019Threatened Democracies: Interdisciplinary Conference in North American Studies, University of Göttingen
Paper: “Fractured Parties and Factional Nominations”
06/2019Intra-Party Politics in Times of Crisis: Party Congress Research Group Annual Meeting, University of Strathclyde
Paper: “Intra-Party Factionalism and Ideological Competition in US Congressional Primaries”
11/2018Annual Meeting of the Political Science Section of the German Association for American Studies, Passau University
Paper: “Mediators of Faction: The Transformation of the Congressional Primary”
* virtual conference due to COVID-19, proposal accepted, conference paper written and shared with participants, presentation delivered virtually.
~ conference cancelled due to COVID-19, proposal accepted, conference paper written and shared with panelists


2019BA Seminar – Polarization in US Politics
2018-2019 Teaching Assistant, Political Science, Understanding North America


2017-2019MA North American Studies
John-F-Kennedy Institute for North American Studies, Freie Universität Berlin – 1.0 Master Thesis: Mediators of Faction: Ideological Competition in Congressional Primaries
2005-2008BA Politics
University of Exeter – 2:1 Hons


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