Teller County Republican Carl Andersen on Tuesday asked a judge to reverse a ruling by state election officials that Andersen didn’t submit enough valid signatures to qualify for the primary ballot in Colorado’s 7th Congressional District.

On Friday, the Colorado Secretary of State’s Office informed Andersen that his nominating petitions fell 455 signatures short of the required 1,500 valid signatures from fellow Republicans who live in the Jefferson County-based district. According to a statement of insufficiency, Andersen’s petitions had 1,045 valid signatures after 3,417 of the 4,462 signatures his campaign submitted were rejected. 

Almost immediately, Andersen told Colorado Politics that he planned to challenge the decision in court, saying he was confident he submitted more than the required number of valid signatures.

“Once Colorado law is properly applied, more than sufficient signatures must be counted and Anderson thereby placed on the ballot,” Andersen’s Washington, D.C.-based attorney Michael Francisco said in a lawsuit filed against Colorado Secretary of State Jena Griswold in Denver District Court.

The lawsuit claims Griswold’s office rejected more than 1,750 signatures that should have counted, including some the lawsuit argues were rejected “for trivial missing information, and many … for claimed ‘signature mismatch.'”

Since 2017, Colorado law requires election officials to verify whether voters’ signatures on candidate petitions match signatures on file. The law was passed in response to a scandal involving forged signatures discovered on petitions submitted by a Republican U.S. Senate candidate.

According to documents filed Friday by Andersen’s campaign with the Federal Election Commission, Andersen paid Oregon-based firm Grassfire $67,329 for petition-gathering services in February and March.

If successful, Andersen, the owner of a construction company, will join economist Tim Reichert, former oil and gas executive Erik Aadland and former legislative candidate Laurel Imer on the June 28 primary ballot for the competitive open seat, which has been held for eight terms by retiring Democratic U.S. Rep. Ed Perlmutter.

State Sen. Brittany Pettersen, a Lakewood Democrat, is her party’s presumptive nominee.

Another Republican seeking the nomination in the same congressional district, attorney Brad Dempsey, said on Friday that he was weighing his options after officials notified his campaign that his petitions contained 251 fewer signatures than required to make the primary. Of the 2,232 signatures submitted by Dempsey, 1,249 were accepted and 983 were denied.

A spokeswoman for Griswold said her office was reviewing the case and declined to comment on the pending litigation but issued a statement about the office’s approach to petition verification.

“The Secretary of State’s Office is committed to upholding the rules around ballot access and the civil servants in the elections division work diligently and with the utmost professionalism to ensure all candidate petitions are processed in a fair and equal manner under the law,” said Annie Orloff, the office’s communications director, in an email.

Griswold has until April 29 to certify the primary ballot. County clerks must get ballots in the mail to military and overseas voters by May 14, and clerks start mailing ballots to the bulk of Colorado’s registered voters on June 6. Ballots have to be returned to county clerks by 7 p.m. June 28.