Mr. Trump’s job approval rating rose to 45% in a new Wall Street Journal/NBC News poll, the highest mark of his presidency and up 1 percentage point from June. The survey was taken over a four-day period that started July 15, a day before Mr. Trump’s news conference with Mr. Putin in which he questioned the conclusion of U.S. intelligence agencies that Russia meddled in the 2016 election.

Underpinning Mr. Trump’s job approval was support from 88% of Republican voters. Of the four previous White House occupants, only George W. Bush, in the aftermath of the Sept. 11, 2001, terrorist attacks, had a higher approval rating within his own party at the same point in his presidency.

The survey found Democrats leading by 6 percentage points on the question of which party should control the next Congress, down from a 10-point advantage in June and 7 points in April. Some 49% of voters in the new survey said Democrats should lead the next Congress, while 43% favored the GOP.