We thank Noam Lupu and Jonas Pontusson for their thorough review of our book and their pertinent questions. What do the case studies tell us about the mechanisms through which union strength and partisanship matter? Government partisanship is clear: the case studies document the policies that different governments implemented or—where veto points or coalition pressures forced watering down—tried to implement. Examples of this dynamic include the left in Spain raising the minimum wage and extending improved noncontributory benefits, or the bourgeois governments in Sweden severely cutting unemployment benefits.

Union density works through wage negotiations and restraints on top incomes through mechanisms of implicit regulation, resource constraints, and organizational constraints (Chapter 4). Beyond union density, institutions that strengthen labor by providing protection for temporary workers, rights of works councils, and contract extension can work together or as substitutes to prevent the emergence of a large low-wage sector and wide wage dispersion. Equifinality is why one cannot assign average weights to different mechanisms. Different variables can lead to the same outcome, depending on context.

With regard to the decline of union membership and electoral support for the left, we are relying here on the extant literature. Key factors in the decline of union membership were deindustrialization and the transition to the knowledge economy with the growth of atypical employment. The decline of electoral support for the left concerns the established left parties in particular, not the left block in general. So one must ask why establishment parties in general lost support to challenger parties on the left and the right. Governing through austere times tends to get incumbents punished at the polls.

As for the contention that unions have become less egalitarian as membership has become more white-collar, and left parties have become less redistributive and more focused on middle class and cultural issues, our evidence does not support the argument about unions. On the contrary, Spanish unions pushed hard for an improvement of social policy for outsiders in pensions, unemployment compensation, social assistance, and a comprehensive minimum income scheme (p. 186).

German unions, first in the service sector and then in core industrial sectors, came to support a statutory minimum wage despite a long tradition of bargaining autonomy, and the SPD managed to get it adopted by the Grand Coalition in 2014 (p. 155). For an important challenge to the view implied in this question that social democratic parties lost support primarily among the working class because of a neglect of redistribution in favor of cultural issues, see the contribution of Abou-Chadi and Wagner in Beyond Social Democracy: The Transformation of the Left in Emerging Knowledge Societies (2024), edited by Häusermann and Kitschelt.

Power resources theory will surely continue to help us understand social welfare policies in the new context. The fact that unions and traditionally allied left parties have become weaker and problem pressures and constraints have become more severe does not mean that unions and left parties have become irrelevant. This argument is supported, for example, by the switch from the PP government of Rajoy to the Left government of Zapatero in Spain. This switch was followed by an increase in the minimum wage of 22% in 2019, further increases in subsequent years, and an agreement with unions and employers on a series of important measures to strengthen labor in 2021 (pp. 180–181).

Finally, we address here the prevailing economic rules of the game. Fiscal constraints have emerged in different forms at different times. Capital mobility has constrained the capacity of all governments to tax corporations and top-income earners. European monetary integration had a constraining effect on government spending in the Euro area (David Brady and Hang Young Lee, “The Rise and Fall of Government Spending in Affluent Democracies, 1971–2008,” Journal of European Social Policy, 24 (1), 2014). The sovereign debt crisis and the conditions imposed by the Troika were devastating for Spain’s efforts to reduce inequality and poverty.