Democracies that have proportional electoral systems spend substantively more on welfare policies than those that have majoritarian systems. Theoretical accounts of this empirical regularity are generally tested using macro-level data, leaving micro-level implications untested. In this paper, I take an alternative approach, leveraging the fact that the theories in question make predictions about the electoral coordination between parties and voters around broad-based redistribution under alternative institutional arrangements. To test the theories, I create a novel measure of income-based voting, which captures the sensitivity of vote choice to changes in income and forms the dependent variable in a second stage model. Overall, I find robust support for more proportionality leading to more income-based voting.