© Scott Olson/Getty Images The “No Malarkey” campaign bus of Joe Biden traveling near Humboldt, Iowa, last week.

WAVERLY, Iowa — Midway through Joe Biden’s eight-day bus tour across Iowa last week, a voter in one of about two dozen audiences he addressed wanted to know whether the former vice president who has been preaching political rapprochement had enough fight in him to take on President Trump.

“You’re such a nice guy, Joe,” said David Kuethe, 73, a retired English professor, sparking thunderous applause from a crowd of largely veterans and their family members here on Wednesday. “But here’s the problem, when you get on that stage with that orange guy in the White House — and I hope you’re on that stage with him to debate — you can’t be such a nice guy.”

Biden didn’t hesitate on a trip that showed he was more than willing to deliver some punches — and not just at Trump.

“I am used to bullies,” Biden countered, citing a childhood stutter that made him a target. But he argued he didn’t have to stoop down to their level to win the next presidential election.

The exchange captured the delicate balance that Biden tried to strike as he barnstormed through cities and small towns from one end of this crucial early voting state to the other, giving short speeches in packed but small events with remarks that often laced tender talk of the values of the American heartland with acid-tipped criticism of Trump.

Throughout his stops, Biden positioned himself as a “nice guy,” a candidate who could restore decency to the Oval Office and “do the job on day one,” without delving into the partisan fray at a time when some Democratic voters have signaled a weariness and distaste for political mud fights. But Biden also showed flashes of anger as he attempted to jumpstart his campaign in Iowa, where he has slipped from the polling lead, and to prove he had the stamina to handle a grueling campaign schedule.

In community centers and recreation halls, often strung with lights and plastered in Biden posters — some handmade and picturing his signature aviator shades — he struck a nostalgic tone as he laid out his personal history: a member of a middle-class family who endured his father’s job loss and became a politician who said he remains deeply connected to the values of Middle America. He described such places as Iowa “the core of our human values and decency.”

But his voice became elevated, his words more impassioned, as he spoke of his ability to navigate world crises and willingness to take on what he called bullies, cowards, and dictators. Trump and Russian President Vladimir Putin did not want him to be president, Biden said to cheers.

He took shots at his Democratic opponents in feisty interviews with reporters. One day after he was told in Waverly that he shouldn’t be too nice, Biden demonstrated he wasn’t. He got into a confrontation with an Iowa voter who raised the unproven claim that Biden had “set up” his son to work at a Ukrainian gas company.

“You’re a damn liar, man,” Biden shot back before challenging the man to an IQ test and a push-up contest. Biden later said he probably shouldn’t have challenged him to the pushups — but showed no regret for aggressively pushing back on Ukraine, a controversy that some voters and analysts worry will burden him if he wins the nomination.

Still, he said, he didn’t need to provide a counter narrative to the Ukraine allegations, contending that would only play into the hands of Trump, who was “the only one who did anything wrong.”

“Anybody who knows me in politics, including Trump, knows that I don’t screw around,” he said, sitting with reporters on his bus Thursday night. “But that is not what this [campaign] is about. I think what the American people want to know is how am I going to make their life better.”

Iowa has been a difficult place for Biden in the past. He lagged in the polls here during his 1988 presidential campaign and abruptly ended his bid before the caucuses after a plagiarism controversy. Two decades later he placed fifth in the 2008 caucuses.

This time around, Biden has kept his edge in national polls even as he has fallen behind in Iowa and New Hampshire this fall. His staffers brushed away concerns about his drop here, saying there was still a clear path to victory because of his polling lead in the other early voting states of South Carolina and Nevada.

Starting his Iowa bus tour on the state’s western edge Nov. 30, Biden was joined by high-profile backers as he headed east. Tom and Christie Vilsack were on the first leg — he the former US agriculture secretary and Iowa governor and she a literacy advocate and political force in the state.

Former secretary of state John F. Kerry announced his endorsement of Biden on Thursday and hopped on the bus tour Friday in Cedar Rapids, making three campaign stops with Biden as well as a late-night pizza run.

Longtime friends from their years together in the Senate, the two touted each other’s credentials so heavily it was at times hard to tell who was campaigning for whom.

“The only team that has worked more closely than us is Donald Trump and Vladimir Putin,” Kerry said.

A few voters expressed dissatisfaction over Biden’s refusal to discuss his son Hunter’s dealings in Ukraine. Some came to Biden’s appearances with concerns he would “flub up” or meander, which he sometimes did. Others doubted he had the “oomph” or oratory skills of Senator Elizabeth Warren. And there were frequent comparisons to South Bend, Ind., Mayor Pete Buttigieg, a centrist like Biden who has taken the lead in recent Iowa polls.

But many people who saw Biden on the last several days of the tour in audiences that skewed older and whiter came away pleased, if still undecided. Voters said they trusted him because of his lengthy experience and relationship with Barack Obama and were relieved Biden appeared livelier in person than in his lackluster debate performances. “Sometimes, charisma doesn’t come out until you’re in the same room,” said Lori Kappmeyer, 64, a librarian retired from Iowa State University, where she and her husband, Bob, saw him speak.

The trip helped dispel concerns for some over Biden’s age. The 77-year-old, who generally has maintained a light campaign schedule, finished the bus tour strong at meetings with labor leaders in Cedar Rapids Saturday.

As he campaigned through Iowa, he recorded greetings and birthday wishes on cellphones for attendees’ friends and family who weren’t able to make it, handed children $20 bills for ice cream, and leaned into his own persona. “Look folks,” he often said as he made a point. Even the title of his Iowa tour — “No Malarkey” — emblazoned on his purple and maroon bus, an old-fashioned phrase for “no nonsense,” seemed to resonate with people, although some younger voters were unfamiliar with it.

“People are voting for him because he is the friendly uncle who is not going to ruin anything, and it fits the brand” said Jacob Schrader, 20, a Republican student at Iowa State who is considering voting for Biden and was one of the few young people who knew what “No Malarkey” meant.

Reach Jazmine Ulloa at jazmine.ulloa@globe.com.