How do trade unions exert political influence? One important channel has been the appointment of trade unionists as government ministers. However, this arrangement relies on political parties as gatekeepers. Our theory argues that the incentives for parties to grant trade unions access to ministerial office have shifted in the postindustrial era. Not only have unions become weaker in many democracies, but electoral dealignment and programmatic change have made trade union support more dispensable for political parties. Under these conditions, even strong unions should be less successful in securing ministerial nominations. We test this hypothesis by combining data on electoral dealignment (election studies) and programmatic change (party manifestos) with a novel data set comprising information on the union background of over 4,000 ministers in 16 West European democracies between 1945 and 2020. Our results deepen our understanding of how socio-economic and political transformations affect not only electoral politics, but also the selection of political elites in postindustrial democracies.