Colorado Democrats won’t gain highly-coveted supermajorities in the state legislature after a Republican won in a closely-watched, toss-up race on the Western Slope.

The Associated Press called the race for Senate District 5 Thursday morning when Republican Marc Catlin had about 52% of the vote and Democrat Cole Buerger had 48%.

Two-thirds majorities in the Senate and the House would have allowed the party to make strides toward fundamentally changing Colorado’s Constitution, including the state’s tax, elections and criminal justice systems. It would have also allowed them to override any vetoes from Democratic Gov. Jared Polis.

Senate Democrats would have needed to win three of five competitive races to win a supermajority in the chamber. AP News called three of those races for Republicans, including Senate District 5. 

With several races not yet called in the House, it was unclear Thursday whether Democrats would keep their supermajority in that chamber. Democrats held leads in several key races. 

Democrats will still hold wide majorities in both chambers. 

Senate District 5

Catlin’s campaign and outside groups poured money into the race in the final days of the election. While Buerger was initially outspending his opponent, that changed over the past month. 

Catlin spent a total of $123,000 and Buerger spent $76,000, according to the latest report before election day. 

The vast majority of spending from outside groups came from All Together Colorado, the state Senate Democratic campaign arm, and that group’s Republican counterpart, Senate Majority Fund. 

During the latest reporting period, Senate Majority Fund spent $1.2 million in the race while All Together Colorado spent about $500,000. 

“I’ve never been in a race this close,” Catlin said before the race was called. 

Senate District 5 stretches from the Interstate 70 corridor in Garfield County through the Roaring Fork Valley into Hinsdale County near the southern border of the state. It includes the entirety of Pitkin, Gunnison, and Hinsdale counties and portions of Delta, Montrose, Garfield, and Eagle counties.

Both Catlin and Buerger opted for moderate positions in their campaigns in the coin-toss race. While the district, which had its boundaries redrawn in the 2021 redistricting process, was initially graded as Republican-leaning, some indicators showed it would be a much closer contest. 

Catlin, who has served in the Colorado legislature as a member of the House since 2017, is a well-known name in state politics. He’s developed a reputation as a go-to lawmaker on water policy.