Do Party Rules Matter? An Examination of State Party Bylaws and Congressional Nominations

This paper considers whether the rules governing state political parties help to explain primary election outcomes. I theorize political parties will see lower levels of competition during primary elections when they have bylaws that centralize power within the state central committee. To test this expectation, I created a dataset of state-level party rules by collecting and coding provisions within the bylaws of all 100 state-level Republican and Democratic parties. I operationalize party centralization of power as whether or not elected officials are represented within each party’s formal membership, their state central committee, and whether or not each party has an endorsement or neutrality policy when it comes to contested primaries. I find the centralization of party power does correlate with lower levels of competition in primary elections for the House of Representatives in 2018 and 2020. Specifically, parties are more likely to see uncontested primaries when they guarantee ex-officio state committee membership to their co-partisan elected officials and are more likely to see fewer candidates in general when they guarantee ex-officio state committee membership to their co-partisan elected officials and when they do not have rules that require the state central committee to remain neutral during contested primary elections. While evaluating the causes of this trend is beyond the scope of this paper, these findings appear to be driven by Republican primaries.