This study tests two related mechanisms linking affective polarisation to regime autocratisation, as theorised by McCoy, Somer and colleagues. The first focuses the consequences of variation in the level of polarisation: increases in affective polarisation heighten social conflict and societal tolerance of practices that undermine liberal democratic constraints, thereby facilitating processes of democratic erosion. The second focuses on the consequences of polarisation intensity: episodes of acute affective polarisation are associated with a more pronounced deterioration in democratic quality.

Empirically, the analysis centers the attention on Central and Eastern Europe between 2010 and 2025—a critical setting given the region’s pronounced episodes of polarisation and democratic backsliding alongside cases of institutional resilience. Methodologically, the study combines Time-Differencing Qualitative Comparative Analysis (TD-QCA) with a two-step QCA approach to capture the configurational and temporally sensitive character of the proposed causal mechanisms. By tracing how combinations of affective polarisation, social conflict, and societal tolerance for autocratic practices evolve over time, the study assesses the validity of the theorised pathways.

This work is conducted as part of the R&D and innovation project ‘Political polarisation and its impact on the constitutional framework (PORECO)’ (PID2023-157037-NB-100), supported by the Spanish Ministry of Science and Innovation, and has benefited from Guadalupe Martinez’s international research mobility, funded by the Salvador Madariaga grant.