Is nostalgia a threat to democracy? This study explores the connection between nostalgia and democratic decline, focusing on the East German state of Thuringia as a case study. Thuringia garnered international attention after the Alternative for Germany (AfD) won 32.8% of the vote in the September 2024 election, becoming the largest party. We argue and empirically demonstrate that nostalgia for an illiberal past fosters anti-liberal political attitudes in the present. Political actors can exploit such nostalgia to legitimize and glorify authoritarian or illiberal regimes, mobilizing opposition to the democratic status quo and justifying autocratic governance practices. To investigate these dynamics, we analyze longitudinal, representative survey data from the “Thüringen-Monitor” covering the past 20 years. This allows for a detailed examination of nostalgia for the German Democratic Republic (GDR), its key drivers—such as status loss—and its relationship with democratic attitudes and voting behavior. In addition, qualitative analysis of open-ended survey responses provides deeper insights into the nature of GDR nostalgia and citizens’ perceptions of democracy. Our findings reveal that the AfD capitalized on widespread GDR nostalgia, amplified by skepticism toward democracy and persistent misconceptions about its functioning. These results underscore how nostalgia for an illiberal past can serve as a fertile ground for extremist parties, posing a significant challenge to democratic stability.