The politician, 81, released a video on Thursday, in which he calls Trump, 76, a "coward." The clip is a new ad to support his daughter's reelection bid ahead of the Republicatican primary later this month.
Backing his daughter, who serves as the vice chair of the House select committee investigating the Jan. 6, 2021 insurrection on the Capitol, Dick says, "In our nation's 246-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," the former vice president continues.
He adds: "He is a coward. A real man wouldn't lie to his supporters. He lost his election and he lost big. I know it, he knows it, and, deep down, I think most Republicans know it."
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Dick then says he and his wife Lynne are "so proud" of their daughter, 56, for "standing up for the truth."
He notes that Liz is "doing what's right, honoring her oath to the constitution when so many in our party are too scared to do so."
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Dick then concludes the message by sharing that his daughter is "fearless" in her fight against Trump. "She never backs down from a fight," he explains. "There is nothing more important she will ever do than lead the effort to make sure Donald Trump is never again near the Oval Office and she will succeed."
He adds, "I'm Dick Cheney. I proudly voted for my daughter. I hope you will too."
RELATED VIDEO: Rep. Liz Cheney Brought to Tears by Standing Ovation in Her Home State of Wyoming
On Sunday, Liz received a standing ovation at the groundbreaking ceremony for the Mineta-Simpson Institute at Heart Mountain Interpretive Center in Powell, Wyoming.
The foundation that built the facility "shares the legacy of Heart Mountain, where over 14,000 people of Japanese descent were incarcerated during World War II." The facility was built in honor of politicians Al Simpson and the late Norm Mineta.
Among the crowd members were her father Dick, Simpson and Mineta's widow. As the crowd stood and applauded Liz, tears came to her eyes.
That night she retweeted photos of her teary-eyed in front of the audience. Her caption included a tribute to Norm Mineta and Al Simpson, writing "their lifelong friendship showed what it means to put country ahead of party."
The Wyoming representative has rarely campaigned in her home state due to security concerns, given her vocal investigation into Trump's efforts to overturn the 2020 election.
Trump won close to 70% of the state's vote in the 2020 election and has endorsed Liz's opponent, Harriet Hageman.
In two weeks, on Aug. 16, Liz will face Hageman in the Republican primary. She faces an uphill battle, as Republicans in Wyoming voted to strip Liz of her party affiliation last November. Hageman currently holds a 22-point lead over Liz, as reported by the Casper Star-Tribune.