By Nicholas Riccardi, Associated Press

A federal judge is hearing arguments in a last-ditch lawsuit by U.S. Rep. Doug Lamborn to get his name on the Colorado GOP primary ballot.

U.S. District Judge Philip Brimmer began proceedings Monday morning in Denver.

The six-term congressman from Colorado Springs has requested an injunction putting his name on the June primary ballots after the Colorado Supreme Court ruled last week he had not gathered enough valid voter signatures. The state court threw out signatures collected for Lamborn’s campaign by people who do not live in Colorado.

Lamborn contends that ruling violates the First Amendment rights of the congressman and his constituents. He argues that the Colorado law requiring signature gatherers to live in the state violates the U.S. Constitution.