Do personalist leaders erode public trust in democracy, or are they a symptom of its decline? The election of personalist leaders—whose party cannot effectively check them—and the declining public trust in democracy are often cited as evidence for democratic backsliding. But we lack a theoretical understanding of their dynamics, nor did we have empirical data to examine their relationship globally. This paper, using two novel global datasets based on latent response model, is the first to investigate the causal relations between personalist leaders and public trust in democracy in a long panel of cross-national data.