Legal Case for Brexit Is Surprisingly European

Is Brexit unconstitutional? That’s the key issue in a suit argued this week before the High Court in London. What makes the question especially piquant is that Britain doesn’t have a single written constitution, but rather a complex tradition of constitutional law made up of principles, precedents and practices accrued over generations.

Under those principles, the answer to whether the U.K. can leave the European Union without a parliamentary vote is … maybe. It seems most likely that the High Court -- or the Supreme Court, which will hear an appeal next -- will say that Brexit can be accomplished without it. But to reach that conclusion, the British courts will have to expand existing principles, and grapple with the meaning of the referendum as a political tool. It’s a sad day for the country that arguably invented representative government.