Rep. Ken Buck speaks to the press after the US House of Representatives passes US debt ceiling bill in Washington, DC, on May 31, 2023.
CNN  — 

Republican Rep. Ken Buck, a hardline conservative who has clashed with his own party, will not seek reelection, he announced Wednesday.

“Our movement has always been fueled by immutable truths about human nature individual liberty and economic freedoms,” the Colorado Republican said in his video announcement. “The Republican Party of today, however, is ignoring self-evident truths about the rule of law and limited government in exchange for self-serving lies.”

Buck cited stagnation in Congress and his party’s election denialism as driving factors in his decision to not run in 2024. “I have been here nine years and Congress refuses to deal with the big issues that we need to deal with,” he told CNN’s Kaitlan Collins, pointing to the sustainability of Social Security and Medicare and cutting government spending.

“In addition to that, Republicans who have answers to these issues – and are at least aware of them, and hopefully will work on them someday – have a huge credibility problem because we continue to talk about and lie about the 2020 election as if it was stolen, as if Joe Biden wasn’t the real winner of that election,” Buck said on “The Source.” “I don’t think we can have the credibility we need with the American public if we continue the lies that we’re now telling.”

Buck, a former prosecutor with the Department of Justice, was first elected to Congress in 2014 after an unsuccessful 2010 run for Senate. While a member of the ultra-conservative House Freedom Caucus, he’s broken with his party in recent years on several key issues and become an outspoken critic of former President Donald Trump in the wake of the 2020 election.

His eastern Colorado district is solidly red, and GOP leaders had floated possible candidates to potentially primary him, sources told CNN in September – an effort now saved by Buck’s bowing out of the race.

The House GOP’s narrow majority has magnified the friction between Buck and much of the Republican conference this term.

He was one of the eight Republican members who voted to oust Rep. Kevin McCarthy over the former speaker’s decision to pass a clean spending bill to avoid a government shutdown without the deep spending cuts sought by conservatives. And Buck repeatedly voted against Rep. Jim Jordan for House speaker last month, contributing to the Ohio Republican’s failure to win the speaker’s gavel.

Buck, who serves on the House Judiciary and Foreign Affairs committees, is also one of several House Republicans standing in the way of the right’s push to impeach President Joe Biden. While he has maintained that he is open to impeachment if he sees evidence of high crimes and misdemeanors, he’s also said he doesn’t believe the House has produced any evidence that Biden profited off of his son’s foreign business deals, which the president has denied. Notably, Buck, a senior member on one of the committees helping to oversee the impeachment inquiry, has cast doubt on whether the evidence even exists.

Buck also put himself at odds with leadership last Congress when he teamed up with Democrats on anti-trust legislation and more recently, for criticizing Trump’s legal issues and third presidential campaign.

He has faced blowback from some in his party for voting to certify the 2020 election results and defending Trump critic former Republican Rep. Liz Cheney of Wyoming, the daughter of his former boss, Dick Cheney – whom he served under when the former vice president was a congressman, according to his office.

In his announcement Wednesday, Buck railed against Republicans leaders he said were creating stumbling blocks for the party by “lying to America claiming that the 2020 election was stolen, describing January 6 as an unguided tour of the Capitol, and asserting that the ensuing prosecutions are a weaponization of our justice system.”

“It is impossible for the Republican Party to confront our problems and offer a course correction for the future while being obsessively fixated on retribution and vengeance for contrived injustices of the past,” he said.

Buck’s announcement came just after fellow Republican Rep. Kay Granger, who voted with Buck and others against Jordan for speaker, said she would not being seeking reelection in her Texas district Wednesday.

CNN’s Annie Grayer and Melanie Zanona contributed to this report.