In the past decade, democratic backsliding has emerged as a global reality, prompting prominent democracy scholars such as Anna Lührmann and Staffan Lindberg to declare that 'a third wave of autocratization is here.' Concurrently, the phenomenon of populism has surged in both new and established democracies worldwide. A burgeoning literature has extensively explored the relationship between these two phenomena, delving into the impact of populism on the quality and survival of democratic regimes. However, a critical gap in this literature revolves around the often-overlooked role that political support indicators, such as satisfaction with democracy and citizens' trust in specific political institutions, play in the causal link between populism and autocratization. This paper aims to address this gap, also considering another vital variable—polarization—and its role in the causal chain leading from populism and political support indicators to autocratization. To investigate these phenomena, we employ a mixed-method research strategy, conducting a nested analysis (multivariate analysis plus case study) based on an original dataset encompassing all EU member states from 2005 to 2023. Drawing on key findings from system support theory, classic democratization literature, and recent scholarship on affective and pernicious polarization, we unveil crucial mechanisms connecting the dots in the causal relationship between the socio-cultural-political dimension (populism) and institutional change (autocratization).