HELENA, Mont. (AP) — It didn’t take long for the fallout to begin after Gov. Steve Bullock announced he was going to seek the Democratic nomination in Montana’s U.S. Senate race to challenge Republican Steve Daines.

Four of the five Democratic Senate candidates, including fundraising leader Cora Neumann, have withdrawn from the race — saying Bullock offered the best chance to defeat Daines.

Helena Mayor Wilmot Collins, a former refugee from Liberia, thanked his supporters and called Bullock “the best person for this very crucial moment in time for our country’s democracy.”

Neumann, who raised $650,000 during her five-month campaign, withdrew just a couple of hours after Bullocks announcement Monday morning.

“I know that what matters most is that we come together in the effort to beat Senator Steve Daines,” Neumann said in a statement. “That is why I am withdrawing from the Senate race and throwing my support behind Governor Steve Bullock.”

Mike Knoles, a physicist and mathematician, tweeted Monday morning that he was dropping out.

“This race is too important to let my ego dictate decisions,” Knoles said. Steve Daines “must go, and I will do everything I can to make sure we #FlipTheSenate.”

Last week, as speculation grew that Bullock was considering a run, Democrat Josh Seckinger of Bozeman said he was ending his 16-day campaign to endorse Bullock.

The only other Democrat still in the race as of Monday afternoon was Navy veteran and energy field engineer John Mues of Loma. Mues’ phone went unanswered when an attempt was made to reach him for comment.

Montana’s filing deadline for the June primary on Monday resulted in other candidates coming forward at the last minute.