Electoral Consequences of Legislative Party Switching

How does legislative party instability affect voter support for individual legislators and parties in the next election? The existing literature on party switching has mainly examined the conditions under which a member of parliament (MP) is likely to change party affiliation. However, the effect of switching on voter approval of individual legislators and parties remains under-researched. We address this gap by using survey experiments conducted in four European democracies with varying levels of party switching and diverse electoral institutions. We hypothesise that switching can negatively impact voter approval of individual MPs through three mechanisms: voters may associate switchers with negative character traits, perceive them as ideologically distant, or feel uncertain about their stances. We also expect that voters will view parties as less competent and be less likely to support them if they lose legislators. Conversely, parties that gain MPs should be regarded as more competent and hence receive increased support. Our findings have important implications for understanding electoral outcomes, intra-party politics, and voter representation.