Liz Cheney, Front and Center in the Jan. 6 Hearings, Pursues a Mission

All of which has made for a strange-bedfellows alliance with Democrats who agree with her on little other than her disdain for Mr. Trump. She understands perfectly well why they want her out front, that a Republican face is useful to them. But she has come to believe that the Democrats she is working with are serious about saving the country, too, as she sees it.

“I’m sure it’s as weird for them as it is for me,” Ms. Cheney said of spending so much time with Democrats. She has grown close to some of them, especially Representative Jamie Raskin of Maryland, and several have told her they cannot wait for the day when they can disagree with her again.

“That’ll mean our politics have righted themselves,” she said.

In a separate interview, Representative Adam B. Schiff, Democrat of California and another committee member, acknowledged that teaming up with Ms. Cheney tested expectations. “It was certainly surreal at the beginning,” he said.

But he said Ms. Cheney and her fellow Republican on the panel, Representative Adam Kinzinger of Illinois, have helped Democrats understand better how to frame their arguments to appeal to open-minded Republicans and make a politically charged inquiry less partisan.

If Ms. Cheney feels the stress of the moment, Mr. Schiff added, she hides it well.

“She doesn’t show it,” he said. “She’s tough. She’s tenacious. She’s smart. She has tremendous work ethic. She knows who she is, and I don’t think it’s an exaggeration to say she has remained true to her conservative ideology. It’s that so many in her party have moved away from conservatism to embrace Trumpism. She’s been incredibly consistent.”

One intriguing exception came just this week when Ms. Cheney voted for a bill that would enshrine the right to same-sex marriage into law along with nearly four dozen other House Republicans. Ms. Cheney made headlines in 2013 during a brief Senate campaign when she opposed same-sex marriage even though her sister, Mary, was married to another woman. Liz Cheney said last year that she had been wrong, and Mary publicly praised her courage.