MALCOM, Iowa — Poweshiek County has fewer than 19,000 residents, but the glare of the national political spotlight was focused on this tiny spot between Des Moines and Iowa City as the campaign paths of Sen. Bernie Sanders and former congressman Beto O’Rourke came within a few windmill-covered miles of each other.

Both men spent the weekend campaigning heavily in Iowa and tweaking messages to address some criticisms they’ve received on the campaign trail as they fight for groups of energized and increasingly young voters, who they hope will help them win the Democratic presidential nomination.

For Sanders (I-Vt.), who has been criticized for having little interaction with voters, that meant answering dozens of questions from people in Malcom about whatever they wanted to discuss: student aid for undocumented immigrants, a universal basic income or criminal justice legislation.

At one point during his town hall, an aide warned Sanders they were running short on time and “this will have to be the last question.”

“No,” Sanders replied. “We have time to take one or two more.” Then he took a question about his plan to raise the minimum wage.

For O’Rourke, who has been accused of being heavy on rhetoric and skimpy on policy specifics, it meant talking to voters in all the detail and length he could muster.

“Let me try again,” he said at Grinnell College after being asked a second time for more specifics of his platforms to address climate change and police violence.

“When it comes to police violence against those who they are sworn to serve and protect, I talked about transparency, accountability, tying federal funds to full reporting on use of force and against whom forced is used,” he said. “I talked about invoking the civil rights laws of the United States to transcend local and state jurisdictions to make sure the full weight and power and accountability of the federal government comes into play to make sure we protect the lives of those in our community.”

This weekend in Iowa, he met many who gushed over him, saying he reminded them of John F. Kennedy. But he also encountered skeptics who told him they want the details behind his lofty rhetoric.

“I want to see very specific legislation. I want to see legislative ideas,” said Maya Dru, a 21-year-old sociology major at Grinnell College who asked O’Rourke how voters can trust his words about addressing climate change, given that he voted to explore expanding oil drilling in the Gulf of Mexico. (O’Rourke told her he regretted the vote.)

“I think saying ‘I regret my vote’ is one thing, but they need to somehow make it clear to voters that you will hold the individuals and corporations that [contribute to] climate change responsible,” she told The Washington Post.

Dru said she was miffed when O’Rourke said he didn’t have a complete answer to her question and would follow up. “What is he going to do, text me?”

She was not the only voter with that reaction.

“He’s talking about Tinder to us,” said Henry Brannan, a 21-year-old sociology and American studies major at Grinnell who is leaning toward Sanders, referring to a common line in O’Rourke’s speech about rural broadband. “His rhetoric in general is clearly aimed at us, but there’s clearly no substance behind it. His website, which I’ve been looking at in recent days, has vision statements. There’s nothing concrete about any of this.”

O’Rourke announced last week that he had raised $9.4 million in 18 days, a clip of more than half a million dollars a day. Sanders leads the Democratic field in fundraising, having raised $18 million in 41 days.

A chunk of that money is going to win over young voters, who have fueled both men’s campaigns in the past. Nearly a third of O’Rourke’s stops during his 16-event blitz of the state in recent days were at colleges, including some that Sanders had stopped at previously. Sanders held an event at William Penn University, and his final one was a short drive from Grinnell College, drawing several Grinnell students.

Both candidates have appeared in Iowa before, so the stylistic differences this time were noticeable. Sanders’s rallies have followed a format similar to his 2016 campaign: an hour-long speech that features Sanders delivering policy prescriptions and applause lines.

But Sanders’s supporters have told him that in retail politicking, his style can be grating to voters in states such as Iowa or with black voters in South Carolina who want to be listened to instead of talked at. The lack of interaction was especially telling when compared with selfie-snapping candidates such as O’Rourke, Sen. Kamala D. Harris (D-Calif.) and Sen. Cory Booker (D-N.J.)

Warming up the crowd before Sanders spoke in Muscatine, former Ohio state senator Nina Turner, a co-chair of Sanders’s campaign, told the crowd: “This is a town hall to go deeper than we usually get to go.”

A few minutes later, Sanders took questions from a dozen people, including Shannon Abel, who lives a block away and asked about soaring Medicare costs.

“I don’t necessarily need politicians to be kissing babies and taking selfies, but I think it’s important to want to have communication with people,” Abel said after the town hall. “I just wanted him to hear my story. I wanted to be heard.”

O’Rourke faced the opposite problem. In many of his Iowa stops, he spent more time answering voters’ questions than delivering his stump speech — then concluded the events taking selfies with attendees.

But his opponents and their supporters have hinted that his rhetoric outweighs his accomplishments, and that he benefits from charm and personality while lacking clear policy ideas. His celebrity connections — he was interviewed by Oprah Winfrey this year and recently appeared on the cover of Vanity Fair — have not necessarily helped.

O’Rourke has time to impress with additional detail, but Sanders has few options when it comes to a question raised by several undecided Iowa voters this weekend: his age. Sanders is 77, and O’Rourke is 46. Several voters, both young and old, who attended O’Rourke events mentioned the age of Sanders and former vice president Joe Biden, who is 76, suggesting concerns about whether they were too old to lead the country.

O’Rourke’s early days as a presidential contender, in which he barnstormed across Iowa, New Hampshire, South Carolina and Nevada and elsewhere with dozens of events, seemed designed to show off his vigor. In his stump speech, the former Texas congressman often touts his ability to woo younger voters, pointing to his losing 2018 Senate race in which the youth vote in Texas was up dramatically.

At a town hall last week at Iowa State University, a young voter asked O’Rourke whether he thought his youth was “a handicap or . . . more of an advantage.”

“Definitely an advantage,” O’Rourke replied, though he didn’t elaborate.

Sanders, who is the oldest candidate in the race, joked about his age onstage, reminding people that “I’m the junior senator from Vermont. The other guy’s older.”

Joanne Alvorez, 27, who is studying for a master’s degree in social work at the University of Iowa, said she likes the college affordability plans Sanders promotes. But she’s turned off by his age.

“I am over old white men leading this country,” she said. “Recently I just think all the old white men that have been doing it haven’t been doing a good job.”