I believe this membership effect to be three-fold: First, trade union membership increases affluent individuals' likelihood to support redistribution. Second, it raises turnout among less affluent individuals. And third, it increases the salience of one's preferences for redistribution when choosing which party to vote for. Focusing on the third effect, I ask in this article: Does redistribution support translate into voting for left parties among union members while non-members are more likely to support right-wing parties even when they support redistribution?
Drawing on Comparative Study of Electoral Systems data from the mid-1990s to the mid-2010s, I argue that unionized individuals are better equipped than non-members to make a party choice reflecting their economic preferences and that redistribution preferences influences members' vote to a higher degree. While the former enlightenment effect mainly affects individuals displaying low levels of political sophistication, the latter increase in salience influences sophisticated and unsophisticated individuals alike. By applying multinomial multilevel logistic models, I argue that trade unions are plausible vessels that enlighten their members about how redistribution support and voting for the left are linked and why voting for a party invested in redistributive policies matters.
