Beyond the State: The Supply-Side Drivers of Cross-Border Political Parties in Europe

The traditional link between political parties and national territory has been fundamentally reshaped by globalization, decentralization, and the integration of the European multilevel system. These forces have shifted political activity beyond the exclusive confines of the state, fostering a diverse landscape of non-state-centered formations. Most notably, cross-border parties have emerged to operate across multiple sovereign jurisdictions. Rooted in the historical tension between state-building and nationhood, such parties commonly articulate irredentist interests or represent territorial minorities whose imagined communities were historically divided through the consolidation of modern state borders. Using a nested research design, this article analyses why and how political parties transcend national boundaries. Moving beyond voter-demand explanations, it focuses on the supply-side of cross-border politics, examining the interaction between a party’s internal structural traits and external institutional incentives. The first stage employs quantitative analysis to test how intra-party organization and institutional incentives- such as party competition, electoral systems, and territorial self-rule- the appearance of cross-border parties. Building on these findings, the second stage utilizes elite interviews to uncover the specific causal mechanisms that facilitate the formation of cross-border party branches. In doing so, this research advances a comprehensive understanding of the emergence of cross-border political parties.