There were just two Republicans present in the House chamber for a moment of silence commemorating the Jan. 6 riot in the Capitol: Representative Liz Cheney of Wyoming, and her father, Dick Cheney, the former vice president.

Ms. Cheney, who has taken a leading role in the special committee investigating the attack, has been ostracized by her party as she continues to condemn former President Donald J. Trump, his lies about the 2020 election, and the Republican Party’s role in helping to spread them, as well as its efforts to play down or deny the severity of the riot.

So while Republican leaders stayed away from the remembrances at the Capitol on Thursday, Ms. Cheney — who was ousted from her leadership post for speaking out against Mr. Trump — was the only elected Republican present in the House chamber on Thursday. Most Senate Republicans issued statements and instead traveled to Atlanta to attend a memorial service for a former colleague. House Republicans remained largely silent.

“The future of the country is at stake, and there are moments when we all have to come together in order to defend the Constitution,” Ms. Cheney told reporters as she left the chamber.

Her father joined her on the House floor, as top Democrats — many of whom regarded him as a detested foe when he served under President George W. Bush — lined up to shake his hand and greet him warmly.

“It’s not a leadership that resembles any of the folks I knew when I was here for 10 years,” Mr. Cheney said, when asked about top Republicans and their response to the riot.

Asked about how they have treated his daughter, he replied, “My daughter can take care of herself.”