Mr. Trump abandoned plans for a final news conference after the NATO meeting, and he called Prime Minister Justin Trudeau of Canada “two-faced” after a video surfaced in which Mr. Trudeau and other world leaders appeared to mock Mr. Trump.

He returns to Washington, where the House Intelligence Committee’s inquiry has concluded, and the House Judiciary Committee is taking up the question of whether to recommend his impeachment.

At the hearings: Three scholars of the U.S. Constitution said that Mr. Trump’s efforts to pressure Ukraine for political gain clearly met the historical definition of impeachable offenses. But a scholar invited by Republicans offered a dissent, calling the Democrats’ case “slipshod.”

What’s next: More hearings are scheduled for next week. House Democrats hope to push the process through to vote on impeachment before their holiday recess begins on Dec. 20, opening the way to a Senate trial in the new year. Read our step-by-step guide to the process.