Support for populist and authoritarian regimes is rising worldwide, despite evidence that they tend to underperform economically. The authors examine the role of (mis)perceptions of regime performance as drivers of political attitudes, leveraging two survey experiments with 11,377 respondents during Argentina’s 2023 presidential elections. Optimistic beliefs about the performance of populist and non-democratic regimes were widespread, and displayed a strong correlation with support for these regimes. When exposed to randomly assigned informational treatments challenging optimistic views about these political regimes, individuals significantly adjusted their beliefs, and reduced their support for candidates they associate with populist and authoritarian leanings. Exploring the impact of different information sources, the paper find that academic sources and newspapers were more influential than social media. Although individuals adjusted their beliefs and attitudes in response to information on regime performance, contradicting their prior beliefs reduced their demand for additional information, consistent with an important role for motivated reasoning.