After holing up at Trump Tower the day after that video was released, Mr. Trump emerged after seeing on television that a crowd of supporters had gathered on Fifth Avenue. He walked through the glass doors, pumped his fist in the air, then walked back into his building, clapping his hands as if cheering himself on.

On Wednesday night, Mr. Trump appeared to rally his own spirits by returning to a favorite topic, his 2016 victory, while taunting the 2020 Democratic presidential field. “She’s gasping for air,” he said of Senator Elizabeth Warren, while poking fun at the pronunciation of Mayor Pete Buttigieg’s name.

The speech — the second-longest he has ever delivered, according to Factba.se, a service that compiles and analyzes data on this presidency — was vintage Trump, hitting on his favorite targets, like Lisa Page, the former F.B.I. lawyer, and James B. Comey, the former F.B.I. director. “Did I do a great job when I fired his ass?” he asked.

After a riff about Mr. Trump’s 2016 presidential rival, Hillary Clinton, his audience briefly reprised a favorite chant from that campaign, “Lock her up.” Some similar shouts were issued in response to Mr. Comey’s name.

Mr. Trump also lashed out at a woman who was escorted from the auditorium by security after interrupting his remarks and making profane gestures, and encouraged security to act more forcefully to remove her. “You got to get a little bit stronger than that, folks,” he said to cheers of approval.

But more than anything, his anger at the House Democrats rang through. He declared that they had embarked on “a political suicide march,” and predicted that Americans would soon vote Speaker Nancy Pelosi “the hell out of office.”

Yet in a false note, the crowd was clearly uneasy when the president attacked Representative Debbie Dingell of Michigan, Mr. Dingell’s widow. Mr. Trump fumed that she had voted for his impeachment even though he ordered the lowering of flags after her husband’s death. “Maybe he’s looking up” instead of looking down, Mr. Trump said.