From Instability to Hostility: Coalition Collapse and Affective Polarization

How do sudden coalition breakdowns shape affective polarization in multiparty democracies? While a growing body of work examines how coalition cooperation structure partisan affect, comparatively little is known about how citizens react when coalitions break apart. We argue that coalition collapse is associated with affective polarization. More specifically, we contend that through a dynamic of scapegoating and blame-attribution, this overall difference is concentrated in greater out-party hostility rather than in-party favorability. We test these expectations by exploiting the abrupt collapse of the German “traffic light” coalition in November 2024, using an Unexpected Event during Survey Design comparing respondents interviewed before and after the collapse. We find that the post-collapse period is associated with higher levels of affective polarization, concentrated in greater hostility toward out-parties rather than stronger in-party attachment. Disaggregating to party-dyads reveals that this hostility is targeted, with dislike rising significantly toward the party publicly blamed for the breakdown, and toward anti-establishment parties, while evaluations of other parties remain stable. Subgroup analyses indicate that this targeted hostility is concentrated among supporters of left-wing parties. Coalition collapses, we argue, do not polarize multiparty electorates uniformly but selectively, along ideologically structured lines. The findings contribute to the literature on affective polarization in multiparty systems by highlighting coalition collapse as a distinct, blame-attribution-based mechanism that is associated with targeted rather than diffuse out-party hostility.