‘I was wrong’: Liz Cheney announces support for same-sex marriage, reversing a longstanding position.

Representative Liz Cheney, Republican of Wyoming, said in an interview on CBS’s “60 Minutes” on Sunday night that she was “wrong” to oppose same-sex marriage, reversing a longstanding position.

“I was wrong,” Ms. Cheney said. “I was wrong.”

Ms. Cheney famously came out against same-sex marriage in a television interview in 2013, while running for Senate in Wyoming, saying she believed “in the traditional definition of marriage.” Mary Cheney, her sister who is gay and married with children, wrote online at the time that Liz was “on the wrong side of history.”

The issue sparked a public rift inside the close-knit and high-profile political family. Dick Cheney, the former vice president and Ms. Cheney’s father, became an unlikely advocate for gay rights when he stated in 2004 that he supported Mary, and that “freedom means freedom for everyone.”

On Sunday night, Liz Cheney said her father had been right the whole time. “I love my sister very much,” she said. “I love her family very much and I was wrong. It’s a very personal issue, very personal for my family. I believe my dad was right and my sister and I have had that conversation.”

She added, “This is an issue that we have to recognize as human beings that we need to work against discrimination of all kinds in our country, in our state.” And she reiterated her father’s famous line: “Freedom means freedom for everyone.”

Ms. Cheney’s reversal on the issue may be more indicative of the country’s evolution on same-sex marriage than any political transformation of her own. Support for same-sex marriage has reached a record high of 70 percent, according to a Gallup poll conducted last June. Among Republicans, support for same-sex marriage was at 55 percent.

Ms. Cheney, who voted to impeach President Donald J. Trump and who was ousted by Republicans in May from her leadership post, has become an unlikely figure of the “resistance.” She has not ruled out a long-shot primary bid against Mr. Trump in 2024 if he decides to run again.

As vice chairwoman of the select committee investigating the Jan. 6 assault on the Capitol, one of only two Republicans on the panel, she has continued to be a vocal critic of Mr. Trump’s lies about the 2020 election.

But in her “60 Minutes” interview, she made it clear that support for same-sex marriage was not part of a larger softening of her conservative stances on many issues.

She reaffirmed that she was anti-abortion and supported gun rights. She insisted waterboarding was “not torture.” She said she did not regret voting to repeal the Affordable Care Act, and she proudly stated that she voted for Mr. Trump’s agenda more than 90 percent of the time.

Gay rights advocates said they viewed Ms. Cheney’s reversal as something more personal than political, noting that her original stance was more surprising than the reversal. “I think it is hard to hold hate against your own sister,” Christine Quinn, the former speaker of the New York City Council, who is gay, said of Ms. Cheney’s reversal. “We have always said that knowing someone personally who is L.G.B.T.+ is the key to changing people’s minds and identifying new allies.”

Ms. Quinn added: “We all learned this year that time together is not a given.”