Congress-watchers are already wondering what the dynamic will be like between her and Mr. Trump — and what messages her body language and expressions will convey — when she stands behind him, captured on television cameras, during the speech.

“That photograph is worth the price of admission,” said Representative Gerald E. Connolly, Democrat of Virginia, who is bringing Amer Al-Mudallal, an Iraq-born chemist who was furloughed from the Environmental Protection Agency during the record-breaking shutdown, along with his wife.

“This is a president — I can’t even say he struggles with empathy; he lacks any signs of an empathic capacity to understand the suffering or plight of other people,” Mr. Connolly said, adding, “I want my guest to give witness, by virtue of being here, to the president that real human beings were negatively affected by your shutdown.”

Members of Congress each get one ticket to bring a guest to the State of the Union address; sometimes they invite family members, but more often they use their tickets to make a point. Addressing gun violence is high on the agendas of several Democrats.

Representative Lucy McBath, Democrat of Georgia, whose son Jordan Davis, 17, was shot to death in 2012 by a man upset that he was playing loud music, is bringing Jeff Binkley, the father of Maura Binkley, 21, who was killed last year in a shooting at a yoga studio in Tallahassee, Fla.

Representative Ted Deutch, Democrat of Florida, is bringing Manny Oliver, whose son Joaquin Oliver was killed at Marjory Stoneman Douglas High School in Parkland, Fla., during the massacre there last year.

“I hope the president will take note of how the American people voted to send a gun safety majority to Congress,” Mr. Deutch said in a statement, “and live up to his previous promises to stand up to the N.R.A. and support meaningful policies to make our communities safer.”