Unlike most other countries, in the United States, subnational governments (states) have substantial authority over collective bargaining and union organization laws. Because states compete for business investment and union (dis)organization likely has spillover effects beyond state borders, weak unions in one state may affect union organization in other states. We examine how union decline in one state is associated with union decline in neighboring states, and whether the presence of prounion (left-leaning) governments may limit the spread of union decline. Examining a period of major union decline (1983-2014), we find that union weakness in one state is associated with union weakness in nearby states. We observe that Democratic power in Congress is associated with higher unionization rates, but that liberal state governments have been relatively powerless to stop union decline in this period. These findings have important implications for understanding the historical and contemporary weakness of American unions and for the future of union strength in the United States.
