Democratic congressional candidate Trish Calvarese on Monday asked a judge to prevent one of her primary rivals, Eileen Laubacher, from participating in the caucus and assembly process to seek the nomination to challenge Republican U.S. Rep. Lauren Boebert in Colorado’s 4th Congressional District.

Calvarese and the party’s congressional district chair, who is currently on leave, argue in the lawsuit filed in Denver District Court that state Democratic Party chair Shad Murib violated state statute when he moved upcoming district assemblies back one day, from March 26 to March 27, to ensure that Laubacher met eligibility requirements under party bylaws.

In an email to party officials, Murib said his decision to push assemblies one day later was “an elegant solution” that ensured an earlier “arbitrary” decision to schedule the CD4 meeting didn’t inadvertently disqualify a candidate from the process.

At issue is whether Laubacher, a retired rear admiral and former top National Security Council staffer, registered as a Democrat in time to try to get on the June 30 primary ballot via the caucus and assembly process.

In her lawsuit, Calvarese argues her opponent missed the deadline by one day and says the state party can’t change the rules at the last minute to favor “establishment candidates.”

Calvarese is also asking the court to issue a temporary restraining order blocking Murib and Secretary of State Jena Griswold, Colorado’s top election official, from allowing Laubacher to access the primary ballot at the congressional district assembly, in a process that kicks off this week at precinct caucuses and county assemblies.

In addition to pursuing support from potential Democratic assembly delegates, Laubacher is also pursuing a spot on the primary ballot by petition, in a process separate from the caucus-assembly route.

Calvarese’s lawsuit wouldn’t affect Laubacher’s ability to qualify for the primary if she gathers enough signatures, but keeping her opponent out of the assembly increases the chances that delegates will designate Calvarese and a third Democrat running for the seat, John Padora, to the ballot.

Calvarese was the Democratic nominee for the seat in 2024 but lost to Boebert by close to 12 percentage points, following Boebert’s move into the heavily Republican district after nearly losing reelection two years earlier in a more competitive district on the other side of the state. Padora sought the 2024 district nomination but finished third in the primary.

The sprawling 4th CD is the only congressional seat in Colorado rated as a safe Republican district. Anchored by suburban Douglas County, the district covers the Eastern Plains and parts of Weld and Larimer counties on the Front Range.

Since joining this year’s primary, Laubacher has raised $6.5 million — more than twice as much as any of Colorado’s other congressional candidates and almost four times the $1.7 million raised by Calvarese.

After spending most of her adult life as a registered Republican, Laubacher changed her registration to unaffiliated before becoming a Democrat on March 27, 2025, just over a month before declaring her candidacy for Congress.

That’s a day too late, Calvarese argues in her lawsuit, pointing out that the Democrats’ 4th CD assembly was originally set for March 26. Party bylaws, she notes, spell out the requirement that anyone “seeking designation to the primary by assembly “must be affiliated with the party for at least twelve consecutive months prior to the date the assembly begins.”

In response to what he characterized as “threatened litigation,” Murib notified party officials on Sunday in an email that he was moving all multi-county assemblies to March 27, the day before the party’s state assembly is scheduled to take place in Pueblo.

“Party Rules are meant to enable participation, not restrict it,” Murib said in the email. “A candidate who registered within the timeframe allowed by our rules shouldn’t be retroactively disqualified because of a logistical decision we made months later to hold the assembly on March 26 — especially when the DSP allows us to hold assemblies up to April 11, 2026.”

Added Murib: “Party bosses shouldn’t pick candidates: voters and delegates do. I’ve said this over and over, and I mean it. Our job is to create a fair process where delegates and ultimately voters make that choice, not to exclude candidates based on technicalities.”

A party spokesman declined on Monday to comment on the lawsuit, saying Murib’s positions were articulated in the email he sent a day earlier.

In a statement issued when she filed the lawsuit, Calvarese called on state party leaders to “enforce rules consistently, follow the law, and end the misguided favoritism toward establishment candidates.”

“Voters deserve to know that while Democrats across this country were fighting to defend democracy, reproductive freedom, and religious liberty, my opponent was still a Republican who couldn’t even be bothered to vote,” Calvarese said.

“We will not win this district with an establishment-backed lifelong Republican,” she added. “We win by taking on the DC corruption, middlemen and monopolies driving up costs for families and buying politicians like Lauren Boebert.”

A spokeswoman for Laubacher’s campaign said her candidate was “very committed to the caucus process” and expects more than 100 veterans will show up at precincts across the district to advocate for Laubacher.

“We want to involve as many people as we can to see who can be on the primary,” Taylor Gillespie told Colorado Politics, adding that the campaign expects to make the primary by both assembly and petition.

“We’ve been working on engaging people through caucus and assembly for months,” she said. “It’s important to engage as many people as we can. This is a time when people want to be involved, and that’s our goal in doing both, is to ensure we have as many people showing support for Eileen and this campaign as possible.”

Padora told Colorado Politics that he believes Laubacher should be allowed to proceed through the assembly, calling efforts to disqualify her “a minor technicality based on a logistical issue.”

“At a time when democracy is under strain nationally, Democrats should model clarity, fairness, and trust,” Padora said. “Let delegates decide. Let voters choose.”

Padora noted that Calvarese faced a similar lawsuit two years ago aimed at keeping her off the ballot, based on whether she met the 12-month voter registration requirement.

“I believe we should follow the rules. It is also clear we need an overhaul so they are consistent, transparent, and applied evenly,” Padora said.

He added that he found it “hypocritical” that Calvarese was now seeking to “weaponize a one-day registration issue to narrow the field” after having herself “pushed the edge of Democratic bylaws and technicalities numerous times.”

A spokesperson for Calvarese told Colorado Politics that the effort to boot his boss from the ballot was a different animal entirely from the lawsuit seeking to bar Laubacher from going through assembly.

“This is about changing the rules to accommodate a lifelong Republican who didn’t switch parties even after Jan. 6th and Roe v Wade was overturned,” the Calvarese spokesperson said, adding that no rules had been changed in 2024 “because there were no applicable rules to change.”