Why is Donald Trump calling himself “Mr. Brexit”?

The Republican candidate for president tweeted out this rather strange message Thursday morning:

At first glance, the tweet seems nonsensical. The United States, of course, is not Britain. It is not even in the European Union. And Trump had no actual involvement in the Brexit referendum, beyond his praising of the result while touring his golf course in Scotland. (Scotland voted heavily to Remain in the EU.)

But, a day after he brought on a leader of the alt-right media to head his campaign, he appears to be associating his campaign with the right-wing movements that have sprung up across Europe, including UKIP in Britain. It is of a piece with his attempt to link Hillary Clinton to Angela Merkel, the German chancellor who has become an enemy of the right for opening Europe’s borders to refugees. He is fully embracing his identity as a force of white nationalism and a disruptor of allegedly corrupt Western institutions.