Replication Data for: Party Sub-Brands and American Party Factions

Scholars and pundits have long noted the dominance of the American two-party system, but we know relatively little about new, endogenous institutions that have emerged within the two major parties. I argue that ideological factions provide party sub-brands, which allow legislators to more precisely define their partisan type and capture faction-specific resources. To support this claim, I analyze new data on nine ideological factions in the House of Representatives (1995-2018). I find that (1) faction voting is distinct, suggesting a product ripe for party sub-branding, and (2) joining a faction changes the ideological composition of a candidate's donor base -- conditional on the strength of the faction's institutions. Party sub-branding is effective only when factions possess organizational features that induce coordinated and disciplined position-taking (e.g., whips, PACs, membership restrictions). These results suggest that, even within highly polarized parties, American political ideology is more than a dichotomous choice, and factions target niche markets of political donors as a means of blunting financial instruments of party power.