PROLE, Iowa — Joseph R. Biden Jr. is coasting in the national polls. Surveys show him ahead of his Democratic rivals in hypothetical matchups against President Trump. He has maintained a lead in Iowa all summer, despite facing months of controversies over his record and his campaign missteps.
But less than two weeks before Labor Day, when presidential campaigns traditionally kick into high gear, there are signs of a disconnect between his relatively rosy poll numbers and excitement for his campaign on the ground here, in the state that begins the presidential nominating process.
In conversations with county chairs, party strategists and dozens of voters this week at Mr. Biden’s events, many Democrats in Iowa described a case for Mr. Biden, the former vice president, that reflected shades of the one his wife, Jill Biden, bluntly sketched out on Monday. “You may like another candidate better, but you have to look at who is going to win,” she said, citing Mr. Biden’s consistent lead in early surveys.
The first ad of Mr. Biden’s campaign, released this week in Iowa, flashed some of his positive poll results against Mr. Trump on screen, and voter after voter cited those numbers in outlining their support for him, saying that defeating the president was their most urgent priority.
That stands in stark contrast to the way voters explain their support for candidates like Senator Elizabeth Warren of Massachusetts, who drew 12,000 people to an event this week in Minnesota, Iowa’s northern neighbor, or Senator Bernie Sanders of Vermont, who also draws large crowds and maintains a core base of die-hard fans.
They and others trail Mr. Biden in most polls and face plenty of their own skeptics, but they also have followings rooted in zealous support for their ideas rather than the political calculus that many voters describe in assessing Mr. Biden.
The former vice president certainly has devoted fans, in Iowa and around the country, and continues to enjoy good will and respect from Democratic voters.
But the risks of a campaign argument that is heavily reliant on strong poll numbers, which can be fickle in a tumultuous election, were on vivid display throughout Mr. Biden’s trip to Iowa, as voters repeatedly emphasized that their support for him was closely linked to what they perceived as his strength against Mr. Trump.
It’s a case they make even as polls have shown several other candidates, namely Mr. Sanders, Ms. Warren and Senator Kamala Harris of California, running strongly against Mr. Trump, and as strategists caution that such theoretical matchups are hardly predictive of an election that’s more than a year away. The polls at this early stage are also partly a reflection of a candidate’s name recognition.
“If there would be a horse leading right now for me, it would probably be Biden, because all the polls indicate he would beat Trump handily,” said Rick Spellerberg, 57, as he waited to see Mr. Biden address a group of voters gathered in a gazebo in Prole, a small rural town, on Tuesday afternoon.
Mr. Spellerberg, of Prole, said that he was “still open” to other candidates and that he was planning to see former Representative Beto O’Rourke of Texas speak afterward.
Asked how Mr. Biden had been doing, Mr. Spellerberg replied, “He hasn’t been doing anything wrong, let’s put it that way.”
Later that day, Mr. Biden addressed another group gathered on a muggy lawn in front of a picturesque barn in Urbandale, as large flies zoomed overhead. Attendees frequently said that Mr. Biden was one of their top two or three choices — again, citing the polls.
“Basically whoever can beat Donald Trump, but I think Biden has the best chance,” said Cheryl Wheeler, 66, of Urbandale. “He’s in the lead, and a proven leader.”
She said she “probably would stick with Biden,” but noted, “I’ll go vote for whoever can do it.”
Samy El-Baroudi, 56, of Des Moines, called Ms. Warren “absolutely amazing, a brilliant woman, brings great ideas.” But Mr. Biden is his current first choice — followed by Ms. Warren and Senator Cory Booker of New Jersey.
Mr. Biden is “human, very electable, which is a major concern,” said Mr. El-Baroudi. “Very real and very sincere, he speaks from the heart. Sometimes that means you put your foot in your mouth. Isn’t that what they liked about Trump?”
A Monmouth University poll from this month showed Mr. Biden leading with the support of 28 percent of likely Iowa caucusgoers — virtually unchanged from the same poll’s results from April.
But Patrick Murray, the director of Monmouth’s Polling Institute, who recently spent time in Iowa, said those numbers did not give the full picture of Mr. Biden’s support in the state.
“I did not meet one Biden voter who was in any way, shape or form excited about voting for Biden,” Mr. Murray said. “They feel that they have to vote for Joe Biden as the centrist candidate, to keep somebody from the left who they feel is unelectable from getting the nomination.”
And JoAnn Hardy, the Democratic chairwoman of Cerro Gordo County, Iowa, where most of the Democratic candidates recently attended the gathering known as the Wing Ding dinner, attributed Mr. Biden’s lead in part to simply being well-known.
“He’s doing O.K., but I think a lot of his initial strength was name recognition,” she said. “As the voters get to meet the other candidates, he may be surpassed soon. I would not be surprised.”
Asked who was poised to do that, she replied: “Elizabeth Warren has the most incredible organization in this state. I could see it being Warren.”
Some of Mr. Biden’s allies view Ms. Warren as his most significant threat in Iowa for now, aware of the extensive organization she built early, her surge in the Monmouth poll and other polls here this summer, and her ability to connect with progressives who traditionally play an important role in the caucuses.
But representatives for the Biden campaign argued that several candidates have risen this summer, only to see their numbers fall back down to earth. His position as poll-leader has been steady up to this point, they stress, though his favorability rating has dipped since he re-entered the political arena, and his advantage has ebbed in some early-state polls.
“We reject the premise that the only reason Biden is doing well in the polls is because of name recognition,” said T.J. Ducklo, Mr. Biden’s national press secretary. “Voters have genuine affection for Joe Biden. They know him and his character, which is why their support for him has been so durable in the face of relentless attacks by all of his primary opponents.”
Yet there have also been self-inflicted controversies. His trip to Iowa earlier this month was marred by multiple gaffes, a dynamic that dominated coverage of the visit and gave some Democrats here pause.
On his visit this week, he was frequently flanked by teleprompters, though he often walked away from them. He misstated the dates of the assassinations of Martin Luther King Jr. and Robert F. Kennedy in a passing remark, something the Republican National Committee seized on.
Still, there are plenty of voters who adore Mr. Biden, praising his experience and his empathy.
“Joe Biden is stability for me, stability and common sense,” Peggy Halterman, 65, of Martensdale, said, describing him as akin to “a member of the family.” She added, “I don’t care about his gaffes. It’s the person inside.”
After a slow organizational start, Mr. Biden’s campaign now appears to have the largest operation in the state, employing about 75 staff members there, both by its count and according to the outlet Iowa Starting Line, which tracks staff hires. The Warren campaign, which has been praised for its creative ground game, claims more than 65 staff members in Iowa.
“We plan to win here, and so that’s why we’ve got such a huge staff,” said Jake Braun, Mr. Biden’s Iowa state director, adding that around 60 of the staff members are devoted to field operations and that the number of volunteers has increased each week. There are 13 offices in the state so far, with plans to keep growing, he said. And Mr. Biden is regularly landing new endorsements in Iowa, including Michael Gronstal, the former majority leader of the State Senate, and several prominent Democrats who supported Mr. Sanders in 2016.
Like Dr. Biden and some of Mr. Biden’s supporters, Mr. Braun cited the polls when asked how Mr. Biden would maintain momentum as other candidates become better-known — and potentially viewed as more viable.
“We are doing better than everybody else in a lot of these key states we need to win,” he said, before going on to describe the coalition Mr. Biden is seeking to build, including outreach to independents, students, white working-class people and people of color.
Yet for all the talk about polls at Biden events, in his own ad and from his own team, Mr. Biden himself, who often insists that he’s more focused on the “marathon” of the campaign, struggled to discuss the issue this week, offering seemingly contradictory statements about how much attention should be paid to polling.
“I notice you didn’t ask me why I’m ahead in all the polls still,” he said in an exchange with a reporter on Tuesday. “I notice you didn’t ask me about how I feel about the new CNN poll. I notice you don’t ask me those things.”
Asked by another reporter if polls should be ignored, Mr. Biden replied, “You already do, so it’s O.K.”
But, he added, “These polls will go up and they will go down. I’ve got to come out here and I’ve got to earn the support of these people.”