The court ruled Lamborn violated state rules when collecting the 1,000 GOP signatures needed to qualify for the primary ballot. State law says the signature collectors must be Colorado residents, and the state Supreme Court determined one of the collectors was not, reversing a lower court decision.
Lamborn plans to challenge the ruling in federal court.
"We are disappointed by the outcome and we believe it was wrongly decided," campaign spokesman Dan Bayanes said in a statement. "We are immediately bringing an action in federal court to overturn the part of Colorado law that deprives voters who have petitioned to have Congressman Lamborn on the ballot of their Constitutional rights."
Candidates can either collect signatures or receive support form 30 percent or more of the GOP delegates gathered at the congressional district’s assembly to qualify for the primary ballot.
Lamborn had already been facing four challengers from the right in a district President Donald Trump carried by 24 points in 2016.
El Paso County Commissioner Darryl Glenn, who ran unsuccessfully for Senate in 2016, submitted petitions for the primary. State Sen. Owen Hill was the only candidate to go through the congressional district’s assembly, earning 100 percent of the delegates’ support.
“I’m encouraged that the court has ruled to protect the integrity of our election process,” Hill said in a statement. “Looking forward to continuing to earn the votes of my friends and neighbors across the district.”
The primary is set for June 26. Inside Elections rates the race Solid Republican.