Which risks are social and which are private? How much of their GDP do states spend on social welfare? Who exactly is entitled to which benefits? Is it still possible to finance an encompassing welfare state in times of deindustrialization, technological and demographic change, and globalization? And why do the answers to these questions differ so much across countries? These and similar questions—all central to social cohesion in capitalist democracies—ensure that the analysis of welfare politics is one of the theoretically as well as methodologically most dynamic and richest research areas within comparative political economy and political science more generally. Besides outlining the comparative development and the difficulty of measuring social policy, the focus of this contribution lies in a critical review of the most important past and current theoretical debates in the field of welfare state research, as a subfield of comparative political economy. These debates include party- and power-resource-centered approaches and their critiques, institutional explanations of welfare state retrenchment and restructuring, and the importance of multidimensional distributional effects for the analysis of social policy. The article concludes with a review of three more recent debates: the importance of public opinion and individual preferences for the development of the welfare state, the interaction of social policy and the changes of party systems, and the increasing relevance of social investment policies. The political and scientific need for innovative political science research will continue for the foreseeable future: Theory building and methodological possibilities are developing quickly, and the welfare states as research subject are constantly being challenged.
