Udall's soldiers have one mission: to get as many Democrats and independents as possible to vote for him between now and Tuesday.
"We are leaving no community untouched," he said.
The next 50 hours or so are crucial for Democrats, who readily acknowledge that they are procrastinators when it comes to voting. Joe Neguse, Colorado's Democratic candidate for secretary of state, told the group that he was lamenting to his fiancee that Democrats weren't voting.
"She said, 'Joe, your ballot is still on the kitchen table,' " Neguse said to the chuckling crowd.
Colorado now makes it very easy to vote by mail or in person, and right now Republicans have an advantage. As of Friday, just over 1.1 million people have mailed in their ballots. About 465,677 of those ballots, or 41 percent, are from Republicans. Democrats have mailed in 371,190 ballots, or 32 percent, and unaffiliated voters have sent in 290,600 ballots, 25 percent of the total.
But Udall and Democrats think that if the total reaches 2.1 million, they will win because of the strength of their ground game -- Udall said his volunteers knocked on 65,000 doors Saturday -- and that a surge of Democratic ballots will be counted after the next mail delivery Monday.
"We feel very good about where we are," Udall said in a brief interview while walking back to his campaign bus. Thornton was the fourth of sixth stops he made Sunday.
"That’s just the way we vote. We take our time, we study the ballot issues," Udall said of Democratic dithering. "You’re going to see a big surge tomorrow with the numbers, and a quarter to a third of the vote will come over the last 48 hours."
Or, as former congresswoman Betsy Markey said, "This is what we do best, our ground game." Markey was defeated by Udall's opponent, Rep. Cory Gardner.
Many of the officials thanked the volunteers for showing up while the Denver Broncos were playing.
"You have some dedicated volunteers to be out here while the Broncos are on," Neguse said. "To hell with the Broncos!" a woman yelled.
Udall was even compared to one of Denver's biggest legends, former Broncos quarterback John Elway.
"You remember The Drive?" Democratic Rep. Diana DeGette said, referring to the time Elway drove the Broncos down the field to score a touchdown that tied them with the Cleveland Browns in the final five minutes of the 1987 AFC Championship game. Elway had the Browns where he wanted them, DeGette said, and the Broncos won in overtime.
"Mark Udall has them where he wants them," she said. "Let's complete that drive."
Volunteers waited to snap photos with Udall, who gladly obliged. One woman asked that he autograph the back of her campaign shirt.
"He's the best," said the woman, Pauline Selig, 71. "He just stands for the people."