Do the electoral constraints imposed by two-party systems make citizens less likely to defect from undemocratic candidates? I employ two innovative candidate choice experiments fielded in England to answer this question. Specifically, I implement two designs manipulating the number and effective number of parties displayed between two and three, exploiting the characteristics of England's party system. Contrary to expectations, I find that Labour and Conservative identifiers do not defect more from undemocratic in-partisan candidates when they face three (effective) parties---Labour, the Conservatives, and the Liberal Democrats---rather than just the two major parties. Instead, defection from undemocratic in-partisans to the out-party drops and relocates to the Liberal Democrats even when the latter have no chance of winning. These findings highlight that having three rather than two parties does not generate more defection from undemocratic politicians---and that voters prefer defecting to the option ideologically nearest to the in-party even when chanceless.
I have change the title of the paper and, generally, updated and improved the manuscript according to the comments I got at APSA 2022. For example, I have included the power analysis and ethical considerations in the main paper.