Former Vice President Dick Cheney, one of the most prominent Republicans in the last half-century, announced Friday will be crossing party lines this election and voting for Vice President Kamala Harris, contending former President Donald Trump "can never be trusted with power again."

"In our nation’s 248-year history, there has never been an individual who is a greater threat to our republic than Donald Trump. He tried to steal the last election using lies and violence to keep himself in power after the voters had rejected him," he said in a statement.

"As citizens, we each have a duty to put country above partisanship to defend our Constitution. That is why I will be casting my vote for Vice President Kamala Harris."

Cheney released his statement hours after his daughter, former Wyoming GOP Rep. Liz Cheney, revealed his intentions. She told "The Atlantic" magazine's Mark Leibovich in an interview at the Texas Tribute Festival that her father believes this is a serious moment in history.

"My dad believes -- and he said publicly -- that there's never been an individual in our country who is as grave a threat to our democracy as Donald Trump is, and that's, that's the moment that we're facing," she said.

Tune in to "This Week" on Sunday, Sept. 8, where co-anchor Jonathan Karl will have an exclusive interview with Liz Cheney.

Both Cheneys have been open about their criticism of Trump following the Jan. 6 attack on the U.S. Capitol by a pro-Trump mob.

Earlier in the week, Liz Cheney said she was going to vote for Harris.

She lost her seat in the 2022 primary to Trump-backed Harriet Hageman by more than 60,000 votes, according to election results.

Cheney made news on another front during her remarks at the festival and said she would support incumbent Texas Sen. Ted Cruz's Democratic challenger Rep. Colin Allred ahead of November. She said that one of the most important things to do to "rebuild our politics is we need to elect serious people."

"You know, there aren't enough good candidates running. I want to say specifically, though, here in Texas, you guys do have a tremendous, serious candidate running for the United States Senate, and his name is ..." Cheney began before being interrupted by an applause "Well, it's not Ted Cruz," she said.

"Colin Allred is somebody I served with in the House ... When you think about the kind of leaders our country needs, and going to this point about [how] you might not agree on every policy position, but we need people who are going to serve in good faith. We need people who are honorable public servants and in this race that is Colin Allred, so I'll be working on his behalf," she continued.

At the same time, Liz Cheney however has been critical of Democratic vice presidential candidate Gov. Tim Walz over recent comments he gave about the Israel-Gaza conflict.

Walz told Michigan public radio WCMU reporters on Thursday that Israel had the right to defend itself and condemned the Oct. 7 Hamas terrorist attack.

Walz then shifted focus to the humanitarian condition in Gaza, saying "the Palestinian people have every right to life and liberty themselves."

"We need to continue, I think, to put the leverage on to make sure we move towards a two-state solution," Walz said. "I think we're at a critical point right now. We need the Netanyahu government to start moving in that direction."

Walz added that pro-Palestinian protesters in Michigan were "speaking out for all the right reasons.

"It's a humanitarian crisis. It can't stand the way it is," he said.

Liz Cheney told Leibovich that she "disagreed" with Walz's answer.

"I do think that that it's very important for us to recognize the extent ... [of] talking about Oct. 7 without mentioning Hamas by name, is not an accurate reflection of the challenges that ... we face and of the attack and the assault on Israel," she said.

ABC News' Ivan Pereira contributed to this report.