Introduction: the European Semester as a new architecture of EU socioeconomic governance in theory and practice

The 'European Semester', a new framework for policy co-ordination across European Union (EU) member states, represents a major step in EU governance. Created in 2010 in the wake of the financial and sovereign debt crises and revamped in 2015, it was intended to provide a new socioeconomic governance architecture to co-ordinate national policies without transferring full sovereignty to the EU level. This introduction offers a brief overview and assessment of the European Semester, examining its implications along three critical axes, running respectively between the economic and the social, the supranational and the intergovernmental, and the technocratic and democratic poles of EU governance. We introduce and briefly summarize the seven other contributions that make up this collection. Our conclusions are that the European Semester challenges established theoretical understandings of EU governance, as it is a prime example of the complexity that supersedes simple polar oppositions.