Democracy is one of the founding values of the European Union (EU) and a guiding principle in its external relations. In the course of the Eastern enlargement, the Union emerged as one of the major democracy promoters. However, the assaults on democratic institutions in some EU member states have undermined the assumption about the positive impact of EU membership on democratic consolidation and sparked a lively discussion whether the Union can safeguard democracy. The EU’s responses to democratic backsliding have attracted a lot of scholarly attention, however, research remains largely confined to the study of sanctions. With the aim to reorient the debate, the article proposes a novel framework to study the EU’s impact after accession and analyses the influence of the Union on democratic reforms in Bulgaria and Romania. Both countries are fascinating cases to explore. Upon accession in 2007 they became the only member states subject to post-accession monitoring through the Cooperation and Verification Mechanism (CVM). Conceived as a short-term instrument to address several ‘outstanding issues’ in the areas of judicial reform and the fight against corruption, the mechanism is yet to be revoked. Despite the limited sanctioning power of the CVM, the trajectories of Bulgaria and Romania have diverged. Thus, challenging the perceived wisdom that EU interventions only matter before accession. The article advances the argument that identifying and exploring the key mechanisms through which EU membership can empower and constrain domestic actors is critical to understanding the differentiated impact of EU democracy promotion and safeguarding.