Measuring and Modelling Escalating Polarization: From Partisan Engagement to Intolerance and Support for Violence

Political hostility between adherents of different political factions in North America and Europe is of increasing concern. Important scientific strides have been made in measuring relevant concepts such as affective polarization, intolerance, and support for political violence among citizens. Further advances have nevertheless been impaired by the lack of a testable model integrating all these components. This study attempts to rectify that situation by introducing the Escalating Polarization (EP) model. Combining insights and findings from the research fields of (1) political behavior and (2) radicalization and extremism, EP provides a unified, causal model of affective polarization and its relationship with intolerance and violence broken down into three stages: Partisan engagement (ingroup identification), Partisan solidification (negative affect) and finally Partisan strife (intolerance and violence). Our study is guided by the question of whether these stages can be validly measured and distinguished, as well as which factors make citizens advance from one stage to the next. We therefore put the model and its subcomponents to the test using a large battery of items measuring affective partisanship, intolerance, and support for violence fielded in two contexts that score among the lowest and the highest in terms of political hostility: (1) Norway (in the nationally representative Norwegian Citizen Panel in May 2019), and (2) the UK (through YouGov in August 2020). Our preliminary analyses indicate that the EP model has merit and that the different stages can be validly measured and distinguished. Our model and data allow to distinguish which factors lead some citizens to move from merely disliking to avoiding, intolerating or even potentially condoning violence against opponents. This knowledge is crucial to formulate effective remedies for excessive polarization.