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If there was ever a sign that Britain is on the verge of a historic mistake, this is it.

Donald Trump reminded the Times of London yesterday that he is in support of the country voting in favor to leave the European Union on Thursday. “I would personally be more inclined to leave, for a lot of reasons like having a lot less bureaucracy,” Mr. Trump told the paper. “But I am not a British citizen. This is just my opinion.”

The Brexit, which partly hinges on anti-immigrant sentiment, is already seen as evidence that Trumpism is a phenomenon that extends well beyond the U.S.’s borders. But to have the actual leader of Trumpism re-endorse the “Leave” campaign just days before the vote makes the connection explicit. After a wild primary campaign that saw Trump dominate his opponents, it looks like America has come to its senses. Will Britain?