“Democratic conditionality” is the core strategy of the EU to induce candidate states to comply with its human rights and democracy standards. How does it work and when is it effective? This paper reports findings of a comparative study of “hard cases”: Slovakia under Meciar, Turkey, and Latvia. We argue that EU democratic conditionality is a strategy of “reinforcement by reward” which works through intergovernmental material bargaining. Its efficacy depends on the candidate governments’ domestic political costs of compliance. By contrast, social influence and transnational mobilization have proven ineffective.