Informed Preferences? The Impact of Unions on Workers’ Policy Views

To what extent, and in what way, do labor unions shape workers’ political preferences? Despite a decline in membership rates, few other organizations have the reach and ongoing access to such a sizable share of the electorate. A key question that arises is the degree to which this access translates into political influence. Empirical analyses often find that union members exhibit political views that are distinct from other workers. But it is unclear whether this is an outcome of the unions’ influence on them, or whether this reflects self-selection, whereby only workers with certain political preferences join the unions in the first place. We address this debate by combining unique data from a targeted survey of American workers and a set of inferential strategies that exploit two sources of variation: differences in the legal choice that workers face when joining or opting out of unions, and over-time reversal in a union’s policy position. Focusing on workers’ stance on trade policy, we offer evidence that unions influence the preferences of their members in a significant and theoretically predictable manner. Moreover, the analysis indicates that self-selection accounts, at most, for a quarter of the estimated “union effect”. The results illuminate the political impact of unions and the broader mechanisms by which citizens form policy preferences. ∗Department of Political Science, Columbia University †Department of Political Science, Tel Aviv University