Gabriel McArthur, a Bernie Sanders delegate to last year’s Democratic National Convention, has withdrawn from Colorado’s 6th Congressional District primary and on Sunday threw his support behind Levi Tillemann, one of three Democrats vying for the chance to take on U.S. Rep. Mike Coffman, the Republican incumbent, in the battleground seat.

“I’ve considered which Democratic candidate understands the best strategy to best Rep. Mike Coffman – a strategy that does not involve moving to the political center. A boldly progressive vision is the only viable path to victory,” McArthur wrote in a Facebook post announcing his endorsement.

“Levi is the only other politician I’m aware of that understands the urgency in addressing the effects of automation on the workforce,” McArthur continued. “He would be also be aggressive in working to transform our energy system, a move that not only would help conserve our natural resources, but would create promising new industries and jobs.” He also lauded Tillemann’s support for working toward a single-payer health care system.

McArthur took some swipes at attorney Jason Crow – one of the other two Democrats running for the seat – saying the “ordained” front-runner has justifiably come under fire from the GOP as the Democratic establishment’s “hand-picked candidate.”

“The American people are completely fed up with politics as usual, and while this certainly should be obvious, the political elite seem frustratingly oblivious to this fact,” McArthur wrote. “Their efforts on the Democratic side to edge out progressives in favor of cookie-cutter candidates like Crow are not only contradictory to the values they claim to espouse, but have only resulted in a Republican supermajority that threatens our way of life.”

Noting that his forebears include a Filipino immigrant and members of the Oglala Sioux Tribe, McArthur said he believes Tillemann understands Democrats have to earn support from minority voters.

The Crow campaign unveiled an endorsement of its own from the Bernie Sanders camp earlier this month.

“The Democratic Party must make way for a new generation of leadership that is committed to restoring America’s promise,” JoyAnn Ruscha, the political director for the Sanders campaign in Colorado last year, wrote in her endorsement. Crow, she said, “believes that working Americans deserve a living wage and he knows that health care is a human right. He’s not afraid to take a stand for public education or equal pay for equal work, because Jason has what Washington lacks: a moral imagination and the courage of his convictions.”

“Jason Crow is not a politician,” Ruscha added. “Rather, he is a breath of fresh air in a stale political climate with a voice we desperately need.”

Democrat David Aarestad, an attorney and one-time candidate for the Cherry Creek School District board, is also running in the suburban, which covers all of Aurora and parts of Arapahoe, Adams and Douglas counties.

McArthur announced he plans to run for secretary of state in next year’s election after withdrawing from the congressional race. The incumbent, Republican Wayne Williams, is running for a second term, and Democrat Jena Griswold has launched a campaign to unseat him.