DES MOINES — Joe Biden has been in public life for more than four decades, has run for president twice in the past and served as vice president for eight years. His third bid for the White House, though long in preparation, is a work in progress.

Biden says his latest campaign is about three big things: to restore the soul of America, to rebuild the spine of the country and to unify a divided nation. By the end of his fifth rally of his first week of active campaigning, it was clear that it is about all that and more.

“I have an ambitious plan to rebuild this country . . . a whole range of things that I’m going to be laying out,” Biden told a rally in Iowa City on Wednesday. “You’re going to be laying out on the floor if I keep going or if I laid it all out.”

That brought laughs from the audience. It was the same a few hours later, when — in the 42nd minute of his speech — he said: “I’m going to get out of your way here. You’re standing so long, and I’m giving you too much detail.” He went on for another 10 minutes before finishing with a rousing call to arms to Democrats to go out and win the 2020 election.

Biden opened his campaign with a video that was tightly focused on the Charlottesville white supremacist rally and President Trump’s following declaration that there were “very fine people on both sides” of that violent clash. Biden used his first rally, in Pittsburgh, to deliver a relatively tight speech focused mostly on the middle class.

In the video, Biden was well scripted. In Pittsburgh, he used a teleprompter. In Iowa he spoke from written notes and text, a combination of script and extemporaneous campaign oratory that moved from one policy topic to another and sometimes back again, that mixed stories he’s told for years with hints of policies to come. At times it was Biden as his most natural; at times it was a jumble.

The people who turned out for the former vice president were open, friendly and sometimes enthusiastic. Some in the crowds on Wednesday were longtime Biden supporters. Others were typical of Iowa activists who are surveying the very large field of Democratic candidates. One woman said Biden was the sixth Democratic candidate she’s listened to in person.

Biden is well-liked and drawing energy based on his implicit message that he is the one Democrat who might be able to settle down the country during turbulent times and draw support from white working-class voters who voted for Trump in 2016. He’s certainly drawn the attention of the president, who on Wednesday morning retweeted posts about Biden almost 60 times.

Two national polls released this week showed Biden receiving a bump in support since his announcement. In those surveys, he holds a healthy lead over Sen. Bernie Sanders (I-Vt.) and the rest of a field that now numbers 21 candidates with Thursday’s entry by Sen. Michael F. Bennet (D-Colo.). Those polls are a mixed blessing. They establish Biden as the party’s front-runner, but they also create expectations and therefore pressure. Future slippage will draw attention, and state polls that run counter will be warning signals.

Those are tactical matters of interest to political insiders. More significant are the questions of what Biden stands for: Where would Biden take the country? Is his campaign about taking the country back to pre-Trump, to restore America to that time and those policies? Or is his campaign about the future? What are the foundational policies that fill out the broad strokes of his early days of campaigning?

On health care, he has not embraced Medicare-for-all but has said he would favor a public option for anyone, regardless of how they get their insurance today or if they are uninsured. He’s also not embraced the Green New Deal, and in Des Moines offered only a few ideas about combating climate change — while noting that he had introduced a climate bill as a senator back in the late 1980s. He talks about reducing college costs, though not by embracing free public college tuition for all.

He talks about income inequality and the gap between corporate chief executives and their workers. He decries the big tax cut championed by Trump that delivered its biggest benefits to those at the top of the income scale. But he does not say exactly whether he would roll it back. He sees tax loopholes and tax expenditures as sources of revenue for other domestic initiatives.

His focus on the middle class is a proxy for the larger message of his campaign, that he is the Democrat best positioned to win back the voters who cost Democrats the industrial states in 2016. He’s long been called “Middle Class Joe.” That nickname, as he said on Wednesday, is not always meant as a compliment, but rather as a way of suggesting he lacks sophistication.

He wears those cuts proudly. What sophistication he has, he said, is in understanding middle America, the hopes and dreams and fears and anxieties of households stretched by real wages that have been mostly flat for decades, by rising college and health-care costs.

Biden argues that what’s wrong is that the “basic bargain” of the past — that workers would share in the benefits of rising profits and a strong economy — has been broken, that it’s been broken for a decade or two. But for eight years, he and President Barack Obama were at the helm.

What progress did they make to restore the basic bargain? Biden can point to the stimulus package that the Obama administration pushed through Congress, which helped prevent the Great Recession after 2008 from becoming even worse. He can point to steady growth during those two terms, though the economy is even stronger under Trump. He can point to the Affordable Care Act, despite its flaws.

He ends his speeches on an upbeat note, one that expresses optimism about the state of the country, of a nation with the most productive workers in the world, with research universities unmatched anywhere in the world, with unlimited potential that he says is the envy of every other world leader. “China is going to eat our lunch?” he asked with a tone of sarcasm in Iowa City. “Come on, man.”

Biden has been road-testing his message for months. The stump speech delivered this week is identical in many ways to those he delivered on behalf of Democratic candidates during the 2018 midterms. But this is a new and different campaign.

Biden highlighted the challenge. “Everybody knows who Donald Trump is,” he said as he closed out his speech in Des Moines. “We don’t have to talk about who he is. We’ve got to let people know who we are.” That starts with the question of who Joe Biden is and where he would lead, after all these years.