OSCEOLA, Iowa — One promises voters that he can heal the gaping emotional and political wounds of the last few years and that his age and experience give him the tools to do the job. The other is new to the national stage, is still trying to connect with African American voters and earnestly argues that his smarts and sensible approach make up for his youth and lack of national political experience.

Welcome to the Reassurance Tour, an Iowa show in which two competing candidates – former Vice President Joe Biden and former South Bend, Indiana, Mayor Pete Buttigieg – are making separate 11th-hour pitches to assure voters each is the best choice to defeat President Donald Trump and reverse much of what the current president has done.

Cartoons on the 2020 Election View All 248 Images

Both are appealing to much the same voter demographic – moderate, and older than the college student crowd drawn to the progressives in the race. In a recent New York Times/Siena College poll of Iowa Democratic voters , 22% of Biden voters would choose Buttigieg as their second choice in the caucuses, and 27% of Buttigieg voters would select Biden as a runner-up. And Iowa will be a test – though with a different grading curve – for both of them.

Biden, 77, talks to voters like he's your doting, calming grandfather, interspersing his remarks with "I'm not kidding folks," And "seriously, think about it. Think about it" as he catalogues the transgressions he says the sitting president has committed.

"He treats NATO like it's a protection racket," Biden said. This is not who we are, guys. Folks, we need a president who knows that this country was not built by Wall Street bankers and CEOs. It was built by ordinary Americans, hard-working Americans. … Think about it, I'm not joking," he went on. "Given the chance, they'd never let their country down. Guess what, the middle class is getting crushed and you all know it."

Buttigieg, meanwhile, sounds like the kid in class who skipped a couple of grades and whose debate team performance is so polished it's hard to tell if he's a natural or just over-prepared.

The 38-year-old Buttigieg's version of the argument is more succinct. Imagine, Buttigieg asked voters at a town hall meeting at the Osceola Fairgrounds, what it will feel like the first morning Trump is not president.

"The reason I'm always asking folks to picture that day is a reminder that it's not the day our problems end. It's the day our work begins," Buttigieg told a crowd of about 150. Is it a risk to pick Buttigieg – the youngest of the field of candidates and someone has never held a political position higher than mayor of Indiana's fourth-largest city?

"The biggest risk you can take is to go up against a president, the likes of which we have never seen … and to try to do it following the same old Washington playbook that brought us to this place to begin with," Buttigieg said. "It's time for something completely different."

Without naming either senator by name, both suggest Bernie Sanders of Vermont and Elizabeth Warren of Massachusetts have proposals that are too expensive and unworkable. That resonates with some Iowa voters worried that if they vote for big change, they'll end up the same guy who's in the White House now.

Former Vice President Joe Biden speaks at a campaign event on Monday in Iowa City, Iowa. Chip Somodevilla/Getty Images

Biden "really spoke to my heart and my soul" at the college campus in Iowa City, says Su Groff-Banarendonk, 65, a special education consultant. "He showed … he has the knowledge, that he can take care of things, the mess we've been left with."

For Steve Stimmel, a 65-year-old retired firefighter, Biden is familiar: He served as vice president to Barack Obama, whom the Iowa City resident supported. Biden has a son in the military, and Stimmel is worried about getting drawn into another war. And "he's older and I'm getting older," Stimmel says wryly, saying Biden would pay attention to health care and matters involving senior citizens.

Age is an issue voters bring up – some worrying that Biden isn't as quick as he once was, and some worried that a candidate as young as Buttigieg might not be able to take on Trump in a national campaign.

"He's got all the experience. He's known," says Michelle Larson, a 53-year-old statistician from Iowa City. But "I think he makes mistakes and that concerns me. He makes good decisions, but the fact that he takes a long time to do that concerns me," she adds.

Buttigieg, meanwhile, has taken some hits for his youth – he tussled with primary foe Sen. Amy Klobuchar of Minnesota over whether he had the experience to run the country. Nor has he attracted young voters: Most polls show that young voters are drawn to Sanders' and Warren's progressive pitches.

But some voters think Buttigieg, or "Mayor Pete," as he calls himself on the trail, is more appealing because of his age.

"We need Pete's energy we need his vitality and youth," says Larry Phillips, a 69-year-old retiree in Osceola.

The Feb. 3 caucuses, political experts here say, may be more determinative for Buttigieg than Biden. The former vice president has struggled here – though he's ahead in a recent USA Today/Suffolk University poll . Since Biden is consistently ahead in polls in South Carolina, where the former vice president enjoys string support among African Americans, he can afford to come in below a couple of other candidates, analysts say.

But Buttigieg, whose home state is nearby and who is having trouble attracting African American voters, needs to show well in Iowa, says Dave Peterson, a political science professor at Iowa State University.

"Iowa is more important for Buttigieg than it is for Biden," Peterson says. "Biden's doing better in national polls. He's got name recognition and can survive doing poorly here. He has some ready-made explanations for why he can do better."

The former South Bend mayor, however, has put a lot into Iowa.