Political scientists have long documented labor unions’ affiliation with the Democratic party (Karol 2009). But as working class voters realign from the Democratic party to the Republican party, how do these changes affect the relationship between unions and the political parties? Due to differences in the parties’ positions on collective bargaining, labor unions remain part of the Democratic coalition for electoral purposes, but experience pressure from rank-and-file labor union members to work with Republicans. As a result, modern labor unions are increasingly likely to build relationships with Republicans and bipartisan coalitions of legislators on policy issues. This project examines how these partisan constraints play out in both electoral and policy settings. Using a novel dataset of emails sent from labor unions, I find that in the period immediately preceding elections, unions are likely to use partisan language compared to their emails sent at other times of the year. Using lobbying disclosure data from the state of Wisconsin, which requires interest groups to register their support or opposition for the legislation they lobby, I expect labor unions to work with an increasing number of Republican lawmakers. As the parties realign, I expect this tendency to work with Republican and bipartisan coalitions of lawmakers to accelerate. Maintaining an electoral relationship with the Democratic party while building partnerships with bipartisan groups of lawmakers on policy issues allows labor unions to support Democratic candidates for office, who support labor unions’ collective bargaining power, while satisfying labor union members’ desire to build relationships with Republican officials. By differentiating between policy and politics, labor unions are able to serve both of these priorities.