Depleting Democracies examines how radical right parties interact with mainstream politics in Eastern Europe and the extent to which they influence democratic quality. It assesses whether their electoral strength, blackmail potential, and coalition relevance translate into real impact, particularly on agendas surrounding minority policy and asylum regulation. The book compares three clusters of countries with varying levels of radical right influence: Bulgaria and Slovakia; Hungary, Poland, and Romania; and the Czech Republic and Estonia. Using a mixed-methods approach, it combines quantitative survey analysis with qualitative comparisons of archival material and political texts to identify the causal role radical right parties play in shaping parties, policies, and democratic outcomes. Advancing theory on radical right actors, the book provides important empirical insights relevant to debates on democratic transformation and the broader effects of radical right participation.