The paper makes an attempt to map the Copenhagen criterion of democracy and the rule of law, one of the main instruments governing the biggest enlargement in the Union history. The meaning of it, however, is still as vague today as it was more than ten years ago, at the time of introduction of the criterion. How should democracy and rule of law be interpreted in the context of enlargement? What exactly is required of the candidate countries in order to meet this criterion? Based on the analysis of the documents released by the European Commission, the Council of Ministers and the European Council in the course of the application of the criteria and taking the experience of the previous enlargements into account, the paper outlines the core structure of the criterion and assesses the degree of change brought to the enlargement regulation by the conditionality policy applied by the Union. The paper concludes that the assessment of democracy and the rule of law criterion was not really full, consistent and impartial and that the threshold to meet this criterion was very low. As a result, the Commission failed to establish a link between the actual stage of reform in the candidate countries and the acknowledgement that the Copenhagen political criteria are met.