Obama is, in fact, as good a place to start as any. The U.S. and U.K. have historically been very close allies, but Johnson—a leading voice in the campaign for Britain to leave the European Union—was displeased with the president weighing in on behalf of the “remain side.” In a column in The Sun, Johnson said Obama’s stance was “incoherent. It is inconsistent, and yes it is downright hypocritical.” He also mentioned the incident in which Obama removed a bust of Churchill from the White House (it was, the president noted, only one of several), implying that the removal was “a symbol of the part-Kenyan President’s ancestral dislike of the British empire—of which Churchill had been such a fervent defender.”

It’s not partisan. Johnson was no fan of Obama’s predecessor, George W. Bush, whom he called “a cross-eyed Texan warmonger, unelected, inarticulate, who epitomizes the arrogance of American foreign policy.”

Obama, of course, is on his way out of the presidency. But that won’t necessarily mend fences between the two countries. On the one hand, the winner of the presidential election could be Hillary Clinton, of whom Johnson wrote in 2008, “She’s got dyed blonde hair and pouty lips, and a steely blue stare, like a sadistic nurse in a mental hospital.” To be fair, Johnson concluded that he wanted Clinton to win that election—though only because it would bring Bill Clinton back to the White House, a reasoning that would probably not endear him to Hillary Clinton.

On the other hand, Donald Trump could also win. The presumptive Republican nominee previously speculated that he was “not going to have a very good relationship” with then-PM David Cameron, a Johnson frenemy of long standing. But don’t count on shared disdain for Cameron bonding the two barmily bouffanted blonds. As mayor of London, Johnson lashed out at Trump for insulting the city with “complete and utter nonsense,” saying that “the only reason I wouldn't go to some parts of New York is the real risk of meeting Donald Trump.” He later said he was “genuinely worried” that Trump might win, and described being mistaken for the entertainer as the low point of a visit to his hometown.

As of press time, Johnson doesn’t appear to have insulted Libertarian nominee Gary Johnson, but there’s still plenty of time.

Closer to home, European leaders had no reason to be fond of Boris even before Brexit. As former Times of London journalist Martin Fletcher wrote:

For decades, British newspapers have offered their readers an endless stream of biased, misleading and downright fallacious stories about Brussels. And the journalist who helped set the tone — long before he became the mayor of London or the face of the pro-Brexit campaign — was Boris Johnson.

His new boss, May, recently mocked him for being incapable of standing up to hard-nosed Teutonic negotiation, remembering an incident in which he bought second-hand water cannons to fight riots but never used them. “Boris negotiated in Europe,” the prime minister quipped. “I seem to remember last time he did a deal with the Germans, he came back with three nearly new water cannon.”