Civic associations underpin American democracy. How can politically cross-cutting associations engage members who hold divergent viewpoints amidst increasing partisan polarization and nationalization of politics? I examine this question in the context of labor unions, studying how unions engage members who hold conservative views at odds with some of the union’s political actions. Using original surveys of local union presidents, members, and non-members along with in-depth interviews in selected local unions, I show how local union leaders can foster norms of participation among politically cross-pressured members. Norms of participation increase conservative members’ perceptions of political representation and engagement in politics, including participation in the union’s political action committee and support for union political mobilization. These findings have implications for understanding civic associations and participation in an era of political division, as well as the role unions continue to play in politics.