Public sector unionization rose dramatically during the 1960s and 1970s – even as private sector unions declined – and by 2010, membership in public sector unions surpassed that of private sector unions. They are now a mainstay of the U.S. labor movement, and wield sizable influence in local, state, and national politics. Yet public employee unions have recently been under political attack, and government employees have suffered losses in employment, compensation and bargaining rights at record levels since the Great Recession. Notably, these assaults have come not just from Republican-led statehouses, but from longstanding Democratic allies.

Public sector unions have traditionally been a bulwark of the Democratic Party, providing Democratic officeholders money and votes. Scholarly accounts emphasize the close alliance Democrats built with public sector unions during the second half of the 20th century. Yet I argue that from the 1990s onward, Democratic-controlled state governments had a hand in weakening public sector unions and undercutting the position of public employees by opting not to expand bargaining rights, and by pursuing pension privatization and cutbacks.

This project delineates public sector union history in four distinct phases (origins, expansion, stagnation and retrenchment), and traces the changing relationship between public sector unions and Democratic Party officials at the sub-national level.  I use federal data, state legislative records, and interviews to examine the politics of the

current period of retrenchment. Comparative state-level case studies and a regression analysis of voting on pension legislation in every state legislature reveal that Democratic support for retrenchment hinged on three factors: (1) interest group power and mobilization; (2) efforts of wealthy policy entrepreneurs; and (3) political leadership. I find that public sector unions were able to surmount this more difficult political environment only when labor (1) built coalitions with other interest groups and effectively countered business opposition; (2) secured large Democratic majorities within the statehouse; and (3) won the tacit support of the state’s governor. A looming Supreme Court ruling against mandatory union dues means the political environment for public sector unionization will only become more difficult in future years.