Résumé : Over the past few years, the legal status and the working conditions of platform workers have been among the most debated manifestations of the digital transformation of work. Tense negotiations on the EU platform work directive (from 2021 to 2024) epitomize long-standing conflicts in EU social policymaking, namely the opposition between capital and labour, on the one hand, and resistance to EU involvement or impact on Member States’ social arrangements, on the other. This paper provides an in-depth inquiry of the policy process by focussing specifically on the presumption of employment in platform work, which was first proposed as an EU-wide provision and eventually nationalized with its definition left to national arrangements. Drawing on this case and mobilizing the literature on positive integration entrepreneurship, and politicization, we shed light on the ‘drivers’ and ‘inhibitors’ of EU social regulation. On the one hand, we provide evidence that joint entrepreneurship of the European Parliament (EP) and the European Commission is a primary driver and argue for acknowledging the role of the EP as a key entrepreneur of ‘Social Europe’. On the other hand, divisions in the Council, underpinned by domestic politics, hinder ambitious social policy regulation at EU level in several respects. Furthermore, we tease out the role of politicization and theorize its ambivalent role as both a driver and inhibitor, depending on contingent party political orientations, contextual factors, but also the role played by Council presidencies, so far overlooked in the literature. We conclude that the drivers and inhibitors we identify, and the resulting dynamics of compromise, are relevant beyond the case of platform work. While stressing the crucial, yet ambivalent, role of politicization, our findings cast a shadow on what has recently been described as a great come back of ‘Social Europe’ with the European Pillar of Social Rights.