At a summit to celebrate NATO’s 70th anniversary, President Emmanuel Macron of France gave Mr. Trump a televised tongue lashing on terrorism. He also stood by earlier remarks about the Trump administration’s role in NATO’s “brain death.”

Separately, Mr. Trump, who is deeply unpopular in Britain, heeded a plea from Prime Minister Boris Johnson not to barge into the country’s Dec. 12 election. Mr. Johnson’s advisers fear that an association with the American president would hurt his electoral chances.

Go deeper: President Trump has a history of falling out with his friends.

Yesterday: Mr. Trump said he did not know Prince Andrew, a son of Queen Elizabeth II who has become entangled in the sexual abuse accusations against the convicted pedophile Jeffrey Epstein. Photographs say otherwise.

Today: The U.S. president is scheduled to meet Chancellor Angela Merkel of Germany.