Who Is Mark Baisley? Douglas County's State Senator, Now the Republican Nominee for U.S. Senate

Of everyone running statewide this year, Mark Baisley is the one Douglas County voters have actually elected before. Three times.

An engineer first

Baisley spent three decades in aerospace and software before he ran for anything. His resume runs through NASA's Jet Propulsion Laboratory, Raytheon and Martin Marietta, and he now heads Slipglass, an engineering software company. He was active in Republican politics for decades before he was a candidate, and he was first elected in 2018, to House District 39, which then covered part of Douglas County and all of Teller County. In 2022 he moved up to Senate District 4, an eight-county district whose Douglas County part is the county's rural edge, about 19,889 residents per the redistricting commission: the foothills along the Jefferson County line, the south around Larkspur and the rural east. Castle Rock and Parker are in District 2 and Highlands Ranch, Roxborough Park, Castle Pines and Lone Tree are in District 30; the rest of his district runs west through Teller, Park, Chaffee, Fremont, Custer and Lake counties and part of Jefferson. It is the seat he holds now. Where he lives is a matter of record rather than a single town: he owns a house in Roxborough Park, where his wife is registered to vote, and in 2022 he told Colorado Politics he rents a Woodland Park home in Teller County as the "primary residence of my choosing after the new districts came out," where he is registered; CPR's 2026 profile describes him as the senator who represents Woodland Park.

The 2026 pivot

He began the cycle as a candidate for governor. Through the third quarter of 2025 that campaign had raised about $35,000, and in January he exited the governor's race and announced for U.S. Senate instead, telling reporters his team hoped to raise $25 million. At the state assembly in the spring he was the only Republican to clear 30 percent, so he advanced without a primary. The money never came: through June 30 he had raised $138,147 against Hickenlooper's $10.3 million.

Where he stands

His campaign site, baisleyforsenate.com, lists four planks:

• Affordability and prosperity. In the Senate he says he will "fight to cut federal taxes, roll back job-killing regulations, restore American energy dominance, and make the US a magnet for employers."
• Safe communities. Give law enforcement "the support and funding they need," and "end the dangerous programs that put violent criminals back into our neighborhoods before they've rehabilitated."
• Immigration. Keep the legal system under which "1.2 million people are legally invited to live in the United States" each year, vetted to be "not violent or dishonorable," to be "self-reliant contributors" and to "proudly assimilate into American culture."
• Agriculture. Farmers and ranchers are "the backbone of our domestic economy and national food security"; his answer to their cost pressures is "fighting government overreach, cutting red tape, and backing private sector solutions" rather than new programs.

He got specific in CPR's September 25 voter guide. On housing, he would lower mortgage rates by offering tax breaks to lenders who write loans at the 10-year Treasury yield, about 4.8 percent against a 6.75 percent average 30-year rate: "That would make a really big difference." On property taxes, he calls Colorado's system "a systemic error" and would pursue a national-level fix. On student debt, he would "lean on the universities": require them to pay 50 percent of loans from their endowments, tax foreign-student programs to cover another 30 percent, and leave students with the remaining 20 percent. On immigration, he called the deaths during recent ICE raids in Minnesota and Texas preventable tragedies but supports ICE's duty to "usher out of the country anyone who is a danger to American citizens," and says the more than a million legal immigrants admitted each year is a small enough number that "they assimilate into America's culture." On the filibuster: "I would vote to eliminate the filibuster if my fellow Republicans would be willing to immediately pass the common sense bills that have been queuing up for years." And he wants Colorado to adopt the U.S. Election Assistance Commission's Voluntary Voting System Guidelines, which he says he pushed for unsuccessfully in the state Senate.

Why his county's result matters

Baisley will not win the state; every rating has the race Solid or Safe Democratic, and the fundraising gap is 74 to 1. What his candidacy will produce is a clean measurement of the Republican brand in Douglas County, because he is the one Republican on the statewide ballot whom these voters know from something other than television.

If he carries the Douglas County precincts of his own Senate District 4, the county's rural edge, by a wide margin while Victor Marx and Lauren Boebert struggle in the same precincts, the county's independents are still rewarding Republicans they know and trust, and the party's problem is candidate quality at the top. If he runs no better than Marx, the brand itself has worn out here, and no amount of local familiarity is saving it. Either way, the seat he is leaving is open for the first time in years, and the Collins-Kurth race for it is the one to watch in the southwest county.

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