Tribal Politics

Abstract The Brexit referendum was a pivotal moment in British politics. Not only did it lead to the UK’s departure from the EU, but it also created a new and lasting political divide. In Tribal Politics, we show that this divide was based on two new political identities: Leavers and Remainers. These new tribes rapidly became central to how people saw themselves, others and the world around them. We argue that the creation of new political identities was the result of three contingent factors: issue contestation (intense, high-stakes public conflict), issue expression (individual commitment through voting and political engagement) and issue alignment (the issue cut across traditional party lines). This context transformed a policy question, to which most people were largely indifferent, into a deep-seated identity divide. The groups that formed became new political tribes. Tribal politics is more than policy disagreement—it means people dislike, look down on, and even discriminate against those who belong to opposing political identities. It also shapes how people see the world: influencing factual beliefs, policy preferences, and views of democratic legitimacy. We demonstrate that Brexit identities produced all of these consequences. As many democracies around the world confront deepening divisions about policy issues, it is more important than ever to understand how one political moment can spark lasting political tribalism and why those tribes so often survive long after that moment has passed.