On the evening of the Iowa caucuses, Joe Burns, a 71-year-old convenience store manager here, came to Walnut Hills Elementary School in sharply contested Dallas County with the intention of making up his mind.

Burns and his wife, Mary, who are among Iowa’s vast ranks of undecided voters, followed a line past lost-and-found boxes filled with mittens and scarves and a mural that read “It’s About Respect, Respect Iowa.” In the school’s cafeteria, the county recorder, wearing a blue Mitt Romney sweater, registered voters and handed Burns a slip of paper with the names of the competing candidates. The Burnses sat at one of the miniature children’s tables and mulled who they wanted to be the next president of the United States.

The candidates’ on-the-ground efforts — or on-air advertising blitzes — came down Tuesday evening to homey gatherings of neighbors in community centers, churches and elementary schools across Iowa’s 99 counties. In Dallas County, the state’s fastest-growing jurisdiction, just outside Des Moines, the contenders sensed an opportunity. Romney, who bested Mike Huckabee by four votes here in 2008, courted the growing numbers of Wells Fargo Mortgage employees, medical workers and other white-collar suburbanites. Rick Santorum preached to evangelical congregants of the Point of Grace mega-church. And Ron Paul persuaded farmers in the west to plant his lawn signs in their fields. But as of 7:30 p.m. Tuesday, the candidates had to let go and trust their political ambitions to Iowa voters and the stage-frightened volunteers deputized to woo them.

The first volunteer to arrive, a Rick Perry supporter named Lynn Kozak, claimed a table in the cafeteria closest to the gym, where the caucus would take place. A team of volunteers for Paul, who, per campaign instructions, declined to give their names, took the table next to her and perused the Perry pamphlets. (“He stole our high-school-sweetheart thing,” one Paul volunteer lamented.) Next came Andi Tisor, wearing a “Newt 2012 Iowa Caucus Team” T-shirt and setting up next to the Paul people, joking, “This would be a lot more fun if there was a bar set up here.” Risa Karras, a mild-mannered Romney volunteer, arrived last and quietly handed out stickers opposite the registration table.

Nearby, the Burnses rose from their table, passing the volunteers and nodding hello to neighbors as they made their way to the gym.

Unlike the Democratic caucuses, where factions of supporters try to get neighbors to join them in different parts of the room, the orderly Republicans sat quietly in the bleachers and 240 folding chairs arranged in rows on the glossy hardwood floor. At 7:30 p.m., under basketball backboards and surrounded by campaign posters and the purple and yellow colors of the Waukee Warriors, Adam Fox, a local party official, approached the microphone stand.

“It’s great to see so many people fired up to beat President Obama,” Fox said before leading the room in the Pledge of Allegiance, passing around the “buck bag” for donations for the county party and accepting election as the evening’s caucus chairman.

“Here we go,” he said, opening the “presidential preference” portion of the evening.

The first caucus-goer to take her allotted five minutes at the microphone spoke in support of the struggling Michele Bachmann.

“We can finally ignore the media and the polls and look at our ballots and make this decision,” she said.

The officials then skipped over Herman Cain, the next name on the ballot, and moved on to Newt Gingrich. As Joe Burns watched from the bleachers, Tisor walked to the center of the gym.

“Newt has asked me to share this letter with you tonight,” she said, reading bits of his tax plan and emphasizing his belief in American exceptionalism. “Newt is asking for your vote tonight so that together we can rebuild together the America that we love.”

Next came candidate Jon Huntsman Jr., whom no one spoke for, and then Perry, whom Kozak pitched as an “outsider.” A Paul volunteer then took the microphone, and identifying himself only as “Mike,” read talking points that included “Ron Paul is married to his high-school sweetheart” and he is the “only true Constitution conservative in this race.”

Karras had actually memorized her speech. Of all the candidates, “there is only one who can beat Barack Obama, and that is Mitt Romney,” she said. “No one else comes close.”

The evening’s last speaker, supporting Santorum, was Iowa Secretary of State Matt Schultz, who worked the floor with the microphone.

“I’m telling you, Rick Santorum is the most genuine candidate running in the field,” he said emphatically. “He is not someone you have to worry about or apologize for.”

After the speeches, the Burnses, seated in the back of the room, conferred and filled out their ballots.

As caucus officials collected the paper slips, an exodus of voters moved toward the rear exit. Joe Burns, who didn’t wait around to hear the results, said he voted for Paul even though he wasn’t sure “how far his candidacy would go.” Mary Burns did the same.

The officials arranged the ballots in piles under the careful gaze of the hovering volunteers and began counting. After double checking their results, the county registrar announced the tally to the handful still lingering in the gym.

“Bachmann, five; Perry, 25; Ron Paul, 41; Gingrich, 43; Rick Santorum, 70; Romney, 92.”

The Paul volunteers consoled Tisor, who was already peeling Gingrich posters off the wall. A small crowd built around Karras, the Romney volunteer.

“You did good,” they told her.

Karras accepted the congratulations and said that after everything she had heard about Santorum and Paul, she thought the count might have been closer.

“I’m very pleased,” she said nonchalantly.