Unions, voter turnout, and class bias in the U.S. electorate, 1964-2004

This paper uses individual level data to examine the impact of unions on turnout and assesses the consequences of dramatic changes in union strength and in the composition of union membership since 1964 for the composition of the U.S. electorate. We first estimate individual-level models to test for the distinct effects of union membership and union strength on the probabilities of members and non-members voting, and then test whether the effect of individual union membership and overall union strength varies across income levels. We find that unions increase turnout of both members and non-members. By simulating what turnout would be were union membership at its 1964 level, we show that the decline in union membership since 1964 has affected the aggregate turnout of both low- and middle-income individuals more than the aggregate turnout of high-income individuals. However, while class bias has increased as a consequence of the decline, the change is surprisingly small.