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Major shake-up in crowded Republican primary for Colorado governor as one candidate leaves race, another leaves GOP

KSJD | By Jesse Paul

Published January 7, 2026 at 12:53 PM MST

Sen. Mark Baisley smiles during an event announcing the move of the Sundance Film Festival to Boulder, on March 27, 2025 outside the Boulder Theater.

The crowded Republican primary race for Colorado governor received a major jolt in recent days.

State Sen. Mark Baisley, a Woodland Park Republican, filed Monday to leave the race to run instead for U.S. Senate.

“With my campaign staff — we’ve talked about it for about three weeks,” he said in an interview with a conservative podcaster announcing his decision. “My focus is now on the U.S. Senate, where I frankly feel more suited.”

Baisley faces an uphill battle in trying to win the Senate race. He’ll have to start fresh on fundraising and national Republicans have signaled they plan to ignore Colorado’s Senate race this year in favor of more competitive states.

On the flip side, Baisley will likely have a much better chance of making it to the general election as a Senate candidate, where the GOP has struggled to find experienced politicians to try to flip the seat currently held by Democratic U.S. Sen. John Hickenlooper.

Separately, former U.S. Rep. Greg Lopez, another Republican gubernatorial candidate, left the GOP last week to become unaffiliated. He’s still running for governor.

“Both parties raise money better than they solve problems,” Lopez said in a video announcing his decision. “They divide better than they listen.”

Republican candidate for governor Greg Lopez waves during the GOP assembly at the Broadmoor World Arena on Saturday, April 9, 2022, in Colorado Springs.

Lopez said he is not changing his values as he leaves the GOP, but rather “changing who I answer to.”

Leaving the GOP may make it easier for Lopez to get on the ballot. As a Republican, he would have needed to collect support from Republican insiders through the caucus or assembly process or gather 1,500 signatures from voters in each of the state’s eight congressional districts to make the primary ballot.

As an unaffiliated candidate, he will only need to collect 1,000 signatures from voters in each of the state’s eight congressional districts to make the general election ballot.

Lopez was previously a Democrat, becoming a Republican in the early 1990s while he was serving as mayor of Parker. He is on his third consecutive run for governor after losing in the Republican primaries in 2018 and 2022.

Lopez served as the U.S. representative for the 4th Congressional District for a few months in late 2024 and early 2025 following the midterm resignation of Republican U.S. Rep. Ken Buck.