Party Realignment and Single-Issue Voters

This paper studies the effect of a single-issue referendum on political
party realignment. We consider the Conservative Party in the United
Kingdom in the aftermath of a referendum on the British exit from the
European Union. We look at the change in positions of Conservative Members
of Parliament using a novel dataset tracking their opinions on British
membership of the EU and their election outcomes between 2015 and 2022.
Our findings show that MPs who resisted switching to a pro-Leave position
faced significantly higher electoral losses. We then consider various
models of switching, showing that safe seats are strong predictors. These
results highlight the sensitivity of political parties to single-issue
politics, underscoring how such environments can contribute to broader
populist movements in modern democracies.