Replication Data for: Understanding Preferences over Borders

The governance of international borders has evolved into a contentious issue of political competition along the cosmopolitan-nationalistic divide. Despite a strong polarization over the level of border openness, many border security policies are carried by a strong cross-partisan support base. This puzzle suggests that public preferences toward border security might be more context-dependent and prone to framing strategies than previously assumed. We develop a theoretical argument that explains under what conditions citizen preferences over borders are more likely to polarize or to converge, and we examine the effect of concrete border security measures, their justification, and the neighboring country to which they apply. We test our argument with a novel open-ended question on border mental associations and a conjoint experiment among 4,700 Germans. Results show that people attach very similar meanings to the concept of border, and that securitization frames and joint EU border guards are a first-rank choice leading to lower levels of polarization. Greater agreement is driven by left-leaning respondents shifting toward a more favorable view of border closure in response to such proposals. Building fences and migration-related justifications polarize the most across different subgroups. These results contribute to our understanding of the polarization potential of border policies and have important implications for the freedom-security trade-off.