“That’s the greatest vulnerability,” she went on, “us not communicating to our family, friends, and neighbors what’s at stake in this election.”

As the president delivered his address, his visage casting the theater in a soft orange glow, the crowd made sure to vocalize their sense of the stakes. Whenever a Democrat appeared onscreen, the crowd erupted in boos, along with a stray “Send them back!” for Representatives Ilhan Omar of Minnesota and Rashida Tlaib of Michigan.

They saved their loudest jeers for Speaker Nancy Pelosi — laughing as the president appeared to ignore her outstretched hand before the speech, booing as she ripped up her copy after it was over.

As Mr. Trump condemned Venezuela strongman Nicolas Maduro as “a tyrant who brutalizes,” and Ms. Pelosi initially appeared expressionless, one man scoffed. “She loves him!” he shouted. “She’s his pen pal!” And when Ms. Pelosi recoiled at Mr. Trump’s claim that her party supports free health care for undocumented immigrants, twice mouthing “not true,” the same man laughed. “Oh, Pelosi,” he said. “Stew, baby — stew!”

Mr. Trump and his administration, on the other hand, earned deafening cheers. As the president and his cabinet entered the lower chamber, the crowd reacted as if hyping an NBA team’s starting lineup. “BARR!” one man shouted when the cameras panned to William P. Barr, the attorney general. Even the briefest shot of Melania Trump, the first lady, seated in the balcony in head-to-toe black, sparked joy. “So beautiful,” much of the audience could be heard whispering.

Not once in his speech did the president mention the Senate impeachment trial, or the vote set for Wednesday afternoon.

Hours before the address, Ms. Maddock said she was eager to see how Mr. Trump would handle the topic. “They’re talking about how the president, he’s not even going to say the word ‘impeach’ in the speech,” she said of fellow Trump supporters.