Britain left the EU 10 years ago. Its politics has been an unruly mess

Britain's Prime Minister Boris Johnson speaks during his ruling Conservative Party's final election campaign rally at the Copper Box Arena in London, Wednesday, Dec. 11, 2019. Kirsty Wigglesworth/AP hide caption toggle caption Kirsty Wigglesworth/AP LONDON — Brexit fractured the European Union, and broke British politics. The U.K. is about to get its seventh prime minister since June 23, 2016, a decade ago Tuesday, when the country voted 52%-48% to leave the EU after more than four decades of membership. Conservative Prime Minister David Cameron, who called the referendum but campaigned for the U.K. to stay in the bloc, quit the next day. His successors have all grappled, largely unsuccessfully, with the consequences of that rupture. The latest is Labour Prime Minister Keir Starmer, who announced Monday that he was stepping down after two years of a sluggish economy, malfunctioning government and a divided and jaded electorate — all legacies, at least in part, of Brexit. Though the decision has faded from headlines, "the subterranean trace of Brexit" still runs through Britain's increasingly unruly politics, said Chris Grey, an academic who has studied the fallout from Britain's EU departure. The Brexit campaign channeled discontent Campaigners for Brexit promised that leaving the then-28 member political and economic bloc would let the U.K. "take back control" of its laws, economy and borders. …