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.本研究探讨单一议题公投对政党重组的影响。我们以英国脱离欧盟（European Union, EU）公投后的英国保守党为研究对象，依托一套新型数据集，追踪2015至2022年间英国保守党议员（Member of Parliament, MP）对欧盟成员国身份的立场变化及其选举结果。 研究结果显示，拒绝转向支持脱欧立场的议员遭遇了显著更严重的选举失利。随后本研究考察了多种立场转换模型，结果表明安全席位是强有力的预测因子。上述研究结果凸显了政党对单一议题政治的敏感性，同时揭示了此类政治环境如何助推现代民主国家中更广泛的民粹主义运动。