The U.K. Supreme Court’s judgment on Tuesday requiring Parliament to authorize Brexit was conservative in the deepest and best sense of the term. Allowing the government to withdraw from the European Union without a parliamentary vote would have enabled the prime minister and her cabinet to change U.K. law on their own, a violation of Parliament’s traditional sovereignty. In practice, if Parliament votes in favor of Brexit, the judgment may not slow down the process very much. But the court nonetheless imposed a respect for orderly constitutional forms -- and required Britain’s elected representatives to take full and individual responsibility for their epochal decision.
Unlike the High Court, whose judgment it was reviewing, the law lords of the U.K.’s highest court avoided high-flown theoretical declarations about the nature of parliamentary sovereignty. Instead, the court presented its ruling as an interpretation of the European Communities Act of 1972, the law that Parliament passed to facilitate the incorporation of European law into U.K. law.