Want to know who's paying for legislative campaign flyers filling Denver mailboxes? Good luck

DENVER - Another Democratic primary in Colorado. Another wave of campaign mailers and attack ads that frequently, as far as the public can tell, emerged from a black hole.

The new glut of spending in state legislative races had already soared past $1.4 million as of early June and will almost certainly increase in dramatic fashion before voting ends in the June 30 primary. The arms race - and spending race - is the latest in an ongoing conflict between outside groups backed primarily by business interests, who prefer more moderate Democrats, and the state's largest unions, which have spent to support more progressive candidates.

The money battle follows a 2024 primary in which outside groups spent $5 million to influence the Democratic races. It's part of a broader tug-of-war for control over Colorado's dominant political party, which has grown into near-supermajority control of the state legislature.

This year's spending is likely to focus on a handful of safe Democratic seats in and around metro Denver. As outside spending has grown in recent years, it has turned some of the safest blue seats in Colorado - like those in Denver - into some of the most expensive contests in the state.

As of Friday, a labor coalition had spent more than $570,000 since May 1 to help more-liberal candidates, while several competing interconnected spending committees had spent nearly double that to help moderates. Six PACs on the moderate side had already raised $769,000, all from two outside dark money groups that disclose few, if any, of their donors.

Most of the money, nearly $500,000, has come from a group called "Fair Economy for Coloradans," which has no publicly disclosed donors. It was created in January by Scott Martinez, Denver's former city attorney. Martinez did not return an email seeking comment.

The rest of the cash comes directly from One Main Street, a prominent financial player in Democratic primaries that favors business-friendly candidates over more progressive challengers.

All six political action committees were registered by Jimmy Dickson, who previously managed two state lawmakers' campaigns, including that of then-Rep. Shannon Bird, who's now running for Congress. Bird co-founded the Colorado Opportunity Caucus, a group of business-friendly Democratic lawmakers that's been financially supported by One Main Street. Dickson, who lives in Durango, did not return a message seeking comment.

Martinez is also the registered agent for the Opportunity Caucus and has served as the caucus's attorney. An email sent to Sen. Lindsey Daugherty, the co-chair of the caucus, and a caucus spokeswoman was not returned.

The six groups backed by One Main Street and Fair Economy - which, despite their financial backers, often seized on the term progressive - are:

-Denver Progressives United, which has run ads backing Denver Rep. Sean Camacho, of Denver, and attacking his challenger, Iris Halpern.

-Adams County United, which is backing Rep. Jacque Phillips, of Thornton, against Gabriel Cervantes.

-Colorado Mountain Progressives, which has directed attack ads against Rep. Mandy Lindsay, of Aurora, and has also spent money backing Chris Floyd for a vacant House seat in the high country, according to the Summit Daily.

-Fighting For A Better Aurora, which is running ads against Rep. Jamie Jackson, also of Aurora.

-Promoting Progressive Women, which has also run ads against Lindsay.

-Progressive Leadership Fund, which has run ads backing Andrés Carrera against Chela Garcia Irlando for a soon-to-be vacant state Senate seat in Denver.

One of Denver Progressives United's ads accuses Halpern, an attorney, of illegally lobbying, based on a complaint filed against her earlier this year. But that complaint was dismissed by the secretary of state's office, as first reported by the Colorado Sun.

Halpern told The Denver Post that she'd sent Denver Progressives United a cease-and-desist letter to stop running the ads and had not received a response.

Just like in 2024, opposing the One Main Street-aligned groups is Colorado Labor Action, which discloses its donors and is financed by the state's AFL-CIO and the Colorado Education Association. It's spent more than $500,000 thus far to back Jackson, Garcia Irlando and Halpern, along with Rep. Kenny Nguyen of Broomfield, who found himself in One Main Street's crosshairs after criticizing the group earlier this year.

Colorado Labor Action has run ads attacking Camacho and Carrera, as well Anne Keke, who is running against Jackson, and Heidi Henkel, who's running against Nguyen.

One Main Street has largely refused to reveal its donors, other than several minority donations from trade unions that it publicly reports. In 2022, it received $25,000 from the Apartment Association of Metro Denver. More recently, federal tax records show One Main Street has received donations from a group funded by the oil and gas industry.

During the 2024 round of well-moneyed primaries, One Main Street received $1 million from " Coloradans for Progress." That group, in turn, received $2.2 million from Chevron and $1.1 million from Coloradans for Responsible Energy Development, another oil and gas group. Tax filings show that One Main Street was the largest recipient of Coloradans for Progress' funding that year.

Andrew Short, One Main Street's executive director, did not return a message seeking comment about the primary campaigns. During the 2024 primary campaign, he denied to The Denver Post that One Main Street was funded by oil and gas interests.

Just like the 2024 primaries, statehouse primary spending is spread out and tangled between multiple groups: Fair Economy has also given $50,000 to the "Colorado Affordability Project," which has been primarily funded by groups representing charter schools, real estate agents and hospitals. Millionaire Kent Thiry, who spent significant sums in the 2024 primaries to support more-moderate candidates, also donated $35,000 to the affordability project group.

Thus far, that committee has launched ads backing Camacho, Henkel, Carrera and Sarah Woodson, who is challenging Lindsay.

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This story was originally published June 14, 2026 at 3:05 AM.