United We Stand? Populism and Party Cohesion: A Comparative Study

This study investigates the ambivalent relationship between populism and party cohesion. While populist parties often project unified fronts against “corrupt elites,” their heterogeneous support bases and anti-establishment origins may foster internal divisions. Using V-Party data, we test whether populist parties demonstrate higher or lower degrees of intra-party unity than traditional parties. Our analysis uncovers a strong negative relationship between populism and party cohesion, challenging the common perception of populist parties as internally unified or monolithic. The comparative analysis also allows for systematically testing several hypotheses related to organizational and ideological features of political parties and the way they interact with populism. Results indicate that organizational characteristics play a significant role: notably, personalism tends to strengthen cohesion, partially offsetting the divisive effects of populism. Additional findings show that right-wing parties generally exhibit lower levels of cohesion compared to their left-wing counterparts. Furthermore, transitioning from opposition to government appears to decrease internal unity within populist parties. These insights deepen our understanding of the structural vulnerabilities within populist movements and underscore the complex interrelations between populism, party organization, and democratic governance.