Relying on post-election surveys, this paper analyzes how class and union

membership condition voters’ abandonment of mainstream Left parties and the

alternatives chosen by former mainstream-Left voters in the period 2001-14.

Inspired by Przeworski and Sprague’s Paper Stones (1986), our analysis shows that

Left parties face a trade-off between working-class and middle-class support and

that unionization renders workers more loyal to Left parties that mobilize middleclass

support. Union membership increases the likelihood that working-class

citizens who abandon the mainstream Left continue to vote. It also increases the

likelihood that voters abandon the mainstream Left in favor of radical Left parties

while it decreases the likelihood that they turn to the radical Right. Controlling for

union membership, middle-class leavers are less likely to abstain from voting and

less likely to vote for the radical Right than their working-class counterparts.

Middle-class leavers are more likely to vote for Greens and for mainstream Center-

Right parties.