Different European democracies react differently to anti-democratic political trends, including the growing power of ‘dubious’ political parties and their leaders. This article focuses on the situation of the Czech Republic and, by tracing the evolution within the party system after 1989, in the light of the assumptions of the concept of militant democracy, seeks to establish whether anti-democratic actions can be prevented by using non-democratic methods and means. Since 2013 we can observe radical changes in the party system and the changing dynamics of party competition. The authors of the article assume that while decommunization remains an important process of shaping the democratic identity of Czechs, it is simultaneously generating Eurosceptic sentiment and leading to an increase in the popularity of parties referring to the communist legacy. The analysis is conducted using the institutional-legal method.