That fickleness was on display again last week, when he called in to a radio show hosted by the ardent pro-Brexit leader, Nigel Farage. Mr. Trump told him that the withdrawal deal Mr. Johnson negotiated with the European Union would preclude a trade agreement between Britain and the United States.
That struck a discordant note, in that Mr. Johnson has promoted his Brexit policy by saying it would open the door to a lucrative deal with Washington. Last weekend, he felt compelled to say in an interview that Mr. Trump was “patently in error.”
On that score, at least, the White House’s characterization of the Wednesday phone call could be seen as helping Mr. Johnson. It seemed to suggest that Mr. Trump was no longer troubled by his deal with Brussels and was looking forward to their future negotiations.
The fact that Mr. Johnson’s aides chose to ignore that, and play up his demand that Mr. Trump drop tariffs on British exports suggests they are focused more on voters in Scotland, as well as England’s north, where the Conservatives are targeting Labour loyalists who voted to leave the European Union.
Whether in the phone call or the Farage interview, Mr. Trump’s remarks have been tailor-made for Mr. Corbyn, who said recently that the president was interfering “to get his friend Boris Johnson elected.” The president’s comments did not sit well with Mr. Farage’s listeners either, who bombarded him with complaints that he should not have given Mr. Trump a platform.
“You were crying about how the Americans should not interfere in British political decisions,” said a listener from Essex who identified himself as Jason, “and yet, here you are sitting with him on your show.”
Several callers alluded to an episode in April 2016 when then-President Obama, on a visit to London, warned Britons that if they voted to leave the European Union, their country would be at the “back of the queue” for a trade deal with Washington. Mr. Obama’s remark, which came at the request of Prime Minister David Cameron, was widely judged to have backfired.