A Denver District Court judge on Thursday permitted Democratic congressional candidate Eileen Laubacher to join a lawsuit filed by one of her primary opponents seeking to prevent Laubacher from participating in the party’s assembly process in a bid to qualify for Colorado’s primary ballot.

Laubacher is one of four Democrats running for the nomination to challenge Republican U.S. Rep. Lauren Boebert in the heavily Republican 4th Congressional District, which covers suburban Douglas County and the state’s Eastern Plains.

Judge Mark T. Bailey granted an unopposed motion filed by Laubacher’s attorneys allowing her to intervene in a lawsuit filed last week by Trisha Calvarese, the Democrats’ 2024 nominee in the district, who is seeking a rematch with Boebert.

The judge earlier declined to issue a temporary restraining order sought by Calvarese that would have prevented Laubacher from taking part in the caucus and assembly process, one of the routes Colorado candidates can take to the June 30 primary. The case is set for a hearing on Monday in Bailey’s courtroom.

At the same time, Laubacher’s campaign blasted Calvarese for hiring one of the top Republican attorneys in the state, who has performed extensive legal work for the state Republican Party and whose Colorado Springs-based firm represents the National Republican Congressional Committee, a party organization that works to elect GOP candidates in House races like Boebert’s.

Calvarese argues that a recent change in party rules made Laubacher ineligible to seek delegate support because her opponent registered as a Democrat one day too late to qualify, based on a district assembly schedule promoted by Calvarese’s allies.

Under the state Democrats’ new rule, candidates aiming for the ballot via assembly have to be registered with the party for “twelve consecutive months” before being nominated by delegates. That would have barred Laubacher from going through the 4th CD assembly on the date it was originally scheduled, March 26, since she changed her registration from unaffiliated to Democrat on March 26, 2025, shortly before entering the congressional race.

Laubacher, a retired rear admiral and former top National Security Council staffer, was registered as a Republican for most of her adult life before leaving the party and becoming unaffiliated, prior to registering as a Democrat.

Calvarese is suing Colorado Democratic Party Chair Shad Murib, alleging that when Murib ordered the assembly date changed to March 27, he was unfairly bending the rules to help Laubacher. Also named in the lawsuit is Colorado Secretary of State Jena Griswold, a Democrat and the state’s top election official, who is charged with certifying the primary ballot based on the results of the assembly.

In an email announcing his decision to move certain district assemblies one day later, Murib said it was an “elegant solution” that made sure what he characterized as an “arbitrary” decision to schedule the party’s 4th CD meeting one day earlier didn’t inadvertently disqualify a candidate.

Colorado law allows candidates to earn spots in the primary by winning support from 30% of delegates to their respective assemblies — in a process that starts with precinct caucuses, which were held last week — or by turning in a sufficient number of valid petition signatures. For major party congressional candidates, it takes 1,500 signatures from members of their own party who live in the district.

Candidates can also take both routes, though if they qualify by petition, they only need to get the votes of 10% of the delegates to advance to the primary.

In addition to seeking delegate support at assemblies, Laubacher is pursuing the primary ballot by petition, but she’s also winning well over the minimum number of delegates, according to unofficial, preliminary delegate counts from counties in the 4th CD that have already held their county assemblies.

Of the 62 delegates elected at county assemblies through Friday, Laubacher claimed 40, or roughly 65%, while Calvarese had won 16 delegates, or 26%. Democrat John Padora, who is running again after finishing behind Calvarese in the 2024 primary, has 5 delegates, or about 8%, with one delegate who is uncommitted.

The lion’s share of the 4th CD assembly’s allotted 175 delegates will be awarded at county assemblies on Saturday, when Democrats from the district’s largest counties — chiefly Douglas and Weld counties — hold their meetings. That means that the final results could change dramatically, even though Laubacher holds a wide lead heading into the final set of assemblies before the district assembly convenes nearly two weeks later.

A fourth Democratic candidate, Jenna Preston, is circulating petitions for a spot in the 4th CD primary. Her campaign told Colorado Politics she plans to turn in signatures next week, before the March 18 deadline. The Colorado Secretary of State’s Office has until late April to validate and certify petitioning candidates.

Laubacher released a statement Friday slamming Calvarese for spending money raised from Democratic donors to pay one of the state’s leading GOP-aligned election law firms to try to keep Laubacher out of the assembly process.

Although Calvarese was initially represented by Denver-based Gary Fielder, a self-described constitutional attorney who filed multiple lawsuits alleging fraud in the 2020 election, the Democratic candidate switched legal representation last week to attorneys Christopher Murray and Julian Ellis, who are partners with the First and Fourteenth law firm. Over the years, Murray has been among the Colorado GOP’s primary lawyers. The pair and their firm have also performed legal work for the Republican National Committee, the NRCC and other entities aligned with President Donald Trump.

Laubacher’s campaign called it “deeply troubling” that Calvarese first hired “an election-denying attrorney” to sue the state’s Democratic Party and then hired the Republican firm.

“This is a blatant attempt to damage Eileen Laubacher because Republicans know she’s the strongest Democrat to defeat Lauren Boebert,” Laubacher’s campaign said.

Calvarese’s campaign manager fired back in a statement to Colorado Politics, accusing Laubacher of trying to confuse voters about her history of being a Republican.

“Voters deserve to know that Eileen Laubacher voted for Donald Trump and that the party is rigging the system to help her,” Fiona Boomer said in a statement. “Laubacher is joining this lawsuit to ensure she can go through caucus and assembly for a chance to kick Trisha off the ballot. Why? So that no one continues to poke into her Republican background in this Democratic primary and voters can’t decide on June 30.”