Democrat Mike Johnston suspended his campaign Tuesday for the seat held by U.S. Sen. Cory Gardner, R-Colo.
Johnston, a former state senator who has led a crowded primary field in fundraising, said he doesn't want to run the "expensive and negative" campaign needed to secure the nomination now that former Gov. John Hickenlooper has entered the race.
"I felt clear that the race we were going to have to actually run to win this Democratic primary was going to be expensive. It was going to be negative, and that's not who I am, that's not what I believe," Johnston told Colorado Politics. "I've spent the better part of my life trying to convince people that a different kind of politics was possible and that there was no race that was worth abandoning those principles and running a nasty campaign against a fellow Democrat."
His departure leaves 11 Democrats running to challenge Gardner, considered the most vulnerable Republican senator on the ballot next year. Johnston is the first candidate to withdraw since Hickenlooper jumped into the Senate race Aug. 22 after ending his presidential campaign a week earlier.
Johnston said he was concerned that a "nasty, divisive primary" could increase chances for Gardner to win a second term.
"When you look at the issues on the line right now, whether it's the future of the U.S. Supreme Court, whether it's the climate crisis, whether it's democracy reform, what is at stake if we mess up this race is too big for us to get in the way," he said.
Polls commissioned by Hickenlooper supporters have shown that the popular former brewpub owner and two-term Denver mayor would be the overwhelming favorite in the primary, though Democrats supporting others note that it's still six months before precinct caucuses and nearly 10 months until the primary.
While Johnston didn't make an endorsement Tuesday, he said he wasn't ruling out throwing his support behind one of the candidates.
He said he hadn't considered yet what to do with the money remaining in his campaign account, which totaled more than $2.6 million at the end of the last quarter — more than the combined balances reported by all the other Democrats in the race then.
Johnston said he decided to suspend his campaign during the holiday weekend with his family at a cabin near Fairplay.
He said he doesn't know what's next for him or his supporters.
"I am deeply committed to all the things that drew me to this campaign in the first place. I wanted today to be about my team, and about what they've done to help build this and why we think we can advance those goals the best by actually not being on the ballot but being in the battle."
Since Hickenlooper joined the race, quickly winning an endorsement from the campaign arm of Senate Democrats, many left-leaning primary candidates have trained their criticism on the moderate former two-term governor, some declaring that the Senate nomination won't be a "coronation."
Former state House Speaker Andrew Romanoff, one of the leading primary candidates, blasted Hickenlooper for campaigning against some of the Democrats' more ambitious proposals during his presidential run, including Medicare for all and the Green New Deal, charging that Hickenlooper has been "echoing (Gardner's) talking points" on health care and climate change.
Johnston said he wasn't bothered by the Democratic Senatorial Campaign Committee's support for Hickenlooper, which has been slammed as unfair interference in a primary by others in the race.
"I understand that they have a focus on making sure we win this seat," he said. "I understand the decision."
Democrats consider winning the seat crucial to taking the majority in the U.S. Senate in next year's election.
Hickenlooper had warm words for Johnston after his departure from the race became known.
"Mike Johnston is a friend, a tremendous public servant and a great Coloradan," Hickenlooper tweeted. "He’s always put the good of the state and indeed country first. I know he will continue to help Colorado do great things going forward."
Gov. Jared Polis, who defeated Johnston in last year's gubernatorial primary, expressed a similar sentiment in a statement: “Mike Johnston is an inspirational, smart and effective leader and I know that our state and nation will continue to benefit from his desire to create real change.”