This paper describes trends in union membership and their consequences for electoral politics

in Sweden since the mid-1980s. The paper documents a sharp decline unionization among

blue-collar workers and white-collar employees without university education and argues that

this has weakened support for Left parties. In addition, union membership has become less

closely associated with support for Left parties. We attribute the latter development to increased

competition between unions, decentralization of wage bargaining and welfare-state

retrenchment.