Divided Kingdom: How Brexit Is Remaking the UK's Constitutional Order

Amanda Sloat is a Robert Bosch Senior Fellow in the Center on the United States and Europe at Brookings. She is also a fellow with the Project on Europe and the Transatlantic Relationship at Harvard Kennedy School’s Belfer Center for Science and International Affairs. Her areas of expertise include Turkey and Southern Europe, British politics, the European Union’s foreign policy, and trans-Atlantic relations.

In June 2016, British voters decided in a referendum to leave the European Union, though clear majorities in Northern Ireland and Scotland preferred to remain. Amid the myriad
complexities surrounding the terms of the EU-U.K. divorce, the decision has strained the U.K.’s constitutional arrangements. For example, will Scotland become independent? How would the return of a hard border on the island of Ireland affect the precarious peace there? And could Brexit affect the U.K.’s policymaking abilities and projection of unity on the international stage, given fights over where and how competences returned from the EU will be exercised in the U.K.? Although these debates can look like British navel gazing, they have practical consequences for the United States and Europe.

This paper argues that Brexit will alter not one but two unions: the European Union and the United Kingdom. It begins with an overview of the U.K.’s constitutional arrangements, outlining how power has been devolved to the country’s nations and regions. It then discusses how Brexit has challenged these structures, with a focus on Northern Ireland and Scotland. Next, it considers how political dynamics in London, Dublin, Edinburgh, and Belfast are complicating efforts to resolve these tensions. Finally, it details how Brexit will affect Northern Ireland and Scotland in political and socio-economic terms, and force U.K.-wide debates about unresolved identity issues and the nature of devolved governance.