Oxford, ENGLAND — If all goes well, a crisis like Brexit, which has agonized and divided the United Kingdom, will never happen in America. The British made the mistake of surrendering a chunk of their sovereignty to the European Union nearly a half century ago. Since then, the EU has gradually acquired more control from the U.K. and other member countries.

In 2016, the U.K. rebelled, voting in a national referendum to leave the EU. This created a political split more ugly and bitter than the division in the United States over President Trump. It divides the British elite — liberals, business, academics — from conservatives and most of the working class.