DENVER (AP) — Republican Rep. Ken Buck said Tuesday that he’ll resign next week, narrowing his party’s razor-thin House majority and potentially throwing an obstacle in the way of Rep. Lauren Boebert‘s effort to succeed him.

Buck, a staunch conservative who already declined to run for reelection as he became increasingly critical of his party’s handling of former President Donald Trump, made his surprise announcement in the midst of the House Judiciary Committee’s hearing on Special Counsel Robert Hur’s investigation into President Joe Biden‘s handling of classified documents.

During an appearance on CNN, Buck lamented that he hadn’t been able to ask a question in the hearing yet even though he’s the third-ranking Republican on the committee.

“A lot of this is personal. That’s the problem,” Buck said. “Instead of having decorum — instead of acting in a professional manner — this place has really devolved into this bickering and nonsense,” he said, adding that this was the worst of his nine years in Congress.

Buck’s March 22 departure will trigger a special election to serve the remainder of his term. Under Colorado law, that must happen within 85 to 100 days — or right around the June 25 Republican primary to run in the November race to serve a full term.

Several Republicans are already running to replace him in November, including Boebert, who moved across the state to run for Buck’s more Republican-friendly seat anchored in Colorado’s eastern plains. But a committee of Colorado Republicans will pick the party’s nominee in the special election, and it’s unclear whether they would choose the controversial Boebert, who has no prior ties to the district.

Speaking to reporters Tuesday on Capitol Hill, Buck alluded to the ability of the local Republican committee to effectively choose his heir.

“Whoever fills that seat both for the next Congress as well as the remainder of this Congress will do a great job,” he said.

Buck said that even though he’s resigning, he wants to stay involved politics.

“I just feel there is important work to be done concerning the election and how we choose candidates,” Buck added. “So I want to get involved in this election cycle and make sure we choose the best candidate we can.”

Buck is a former federal prosecutor and District Attorney in northern Colorado who is a member of the ultraconservative House Freedom Caucus. Since the 2020 election, however, he’s made a name for himself in Washington breaking with his party on major issues. He voted to certify Biden’s presidential win, voted against a Republican push to impeach Biden and against making Rep. Jim Jordan, a major Ttump ally, speaker.