Differentiating the sources of post‐election partisan affect warming.

While scholars have closely examined the intensification of negative affect across party lines during elections, less is known about the decline of partisan hostility in the aftermath of election campaigns. Synthesizing insights from research on electoral rules and political psychology, we theorize and empirically test two such mechanisms of post‐election negative affect decline. The first is that of winners' generosity: the expectation that self‐perceived election winners will express warmer feelings towards political opponents. The second is that of co‐governance, which predicts that shared coalition status leads to warmer affective evaluations among governing parties. We provide evidence that these mechanisms operate as pressure valves of negative partisan affect. We also show that while co‐governance reduces negative affect between parties who govern together, it fuels negative affect among supporters of opposition parties. The empirical analyses leverage a uniquely uncertain political period following the 2021 Israeli elections, around which we conducted an original panel study. Our findings advance the comparative polarization literature and connect psychological and institutional accounts of temporal fluctuations in partisan affect. [ABSTRACT FROM AUTHOR]