DES MOINES — It has become political lore, repeated on cable airwaves and by Democratic campaign consultants, even presidential candidates. In 2007, as the story goes, black voters were uncertain about Barack Obama’s presidential candidacy until he won the Iowa caucuses, after which they rallied around him over the onetime front-runner, Hillary Clinton.
Some Democrats had suggested that a win in next Monday’s Iowa caucuses could have a similar influence among black voters in South Carolina and elsewhere, to the detriment of former Vice President Joseph R. Biden Jr., who leads among African-Americans in polls. But in reality, according to historical polling data and interviews with some advisers from the Obama campaign, Mr. Obama’s political strength with black voters was stronger than many remember — even as Mrs. Clinton was ahead in many polls in late 2007 and early 2008.
The persistence of the narrative that Iowa made Mr. Obama has long irritated some of his advisers, who said that this recollection from 2008 had led campaigns astray since then, discounted the agency of black voters and minimized the robust grass-roots strategy that Mr. Obama’s team undertook in the South.
Cornell Belcher, Mr. Obama’s chief pollster in South Carolina, said internal campaign polling data showed Mr. Obama surpassing Mrs. Clinton among black voters in South Carolina as early as November 2007, and leading throughout the entire state before Iowa voted. Public polling shows Mr. Obama with clear leads among black South Carolina voters through that November and December, with his numbers growing further after the Iowa caucuses.
“Black voters aren’t waiting for white people to tell them what to do,” Mr. Belcher said. “It’s racist. It’s racial paternalism.”
He added, “Iowa gave Barack Obama the same thing it will give any candidate that surges that beats the presumptive front-runner. It gives bounce and credibility — but that’s not just among black voting.”
In applying lessons from Mr. Obama’s Iowa victory to the current Democratic primary, Mr. Belcher and other political operatives have grim news for candidates hoping that a win in Iowa can reverse their luck with black and Latino voters across the country: don’t count on it.
This includes Senator Amy Klobuchar of Minnesota, former Mayor Pete Buttigieg of South Bend, Ind., and Senator Elizabeth Warren of Massachusetts, who have showed little traction with black voters in state and national polls. In a new national poll released by ABC News and The Washington Post, 51 percent of black voters were behind Mr. Biden. The next closest candidate was Senator Bernie Sanders of Vermont, who was at 15 percent.
Another recent poll of black voters from The Washington Post and Ipsos, showed Mr. Biden ahead by 60 percentage points with black voters aged 65 and older.
Mr. Belcher said campaigns seeking to challenge Mr. Biden in South Carolina had made a mistake “waiting for this magic Iowa.”
“It’s lazy thinking,” he said. “They think they don’t have to put resources behind it, and is, in fact, taking a key constituency that they need for granted.”
Valerie Jarrett, the former senior adviser to Mr. Obama, said any candidate looking to replicate their 2008 strategy required not only an organizing vision, but also significant resources.
Ms. Jarrett echoed Mr. Belcher, saying she thinks there’s “a good chance” Mr. Obama “would have won black vote in South Carolina even if he hadn’t been competitive in Iowa.”
“Him winning an overwhelming white state sent a message across the nation,” she said. “But was it the only factor? I don’t think so.”
How much the first nominating contest in Iowa truly matters as political kingmakers has been debated for decades. In Iowa, it is common for voters to mention Mr. Obama’s 2008 win as a point of pride, a justification for a state whose primary importance is under intense scrutiny. This election cycle, Iowans who support Mr. Sanders, Mr. Buttigieg, Ms. Warren or Ms. Klobuchar, cite Mr. Obama’s first campaign as a ready-made antidote to their candidate’s lagging status among black and Latino voters. Just do well in Iowa, they argue, and the other voters will follow.
But even as one of Mr. Biden’s senior advisers describe South Carolina and black voters as his “launching pad,” there are signs his position may be more precarious than Mrs. Clinton’s in 2016 and Mr. Obama’s in 2008. Mr. Biden also has below average favorability ratings and has struggled in particular with younger black voters. His polling lead among black voters is about 30 points, commanding but less than the 60-point advantage that Mrs. Clinton experienced in 2016.
Briahna Joy Gray, the national press secretary for Mr. Sanders campaign, has said she believed that winning in the early states would help Mr. Sanders overcome skepticism.
“For legitimate historical reasons, black voters tend to want to back the person they see as the most electable,” Mr. Joy Gray said late last year. “And it sometimes takes a little bit longer to convince people that you are the right person to take out someone like Trump.”
Mr. Sanders’s campaign has been one of many to deploy this line of thinking. Former presidential candidates such as Senators Kamala Harris of California and Cory Booker of New Jersey, both of whom are black, had hoped to unlock support in South Carolina through strong Iowa finishes. At the end of her stump speech during her campaign’s final months, Ms. Harris would tell Iowans about coming to the state during Mr. Obama’s first run, and implored them to help her recreate that historic moment.
Mr. Buttigieg, who has gained traction among white liberals and moderates in Iowa and New Hampshire but has struggled to replicate his support nationwide, has cast himself repeatedly in the mold of Mr. Obama, also alluding to him during speeches on the trail.
“The same state that took a chance on a young guy with a funny name, who a lot of folks didn’t think could win 12 years ago,” Mr. Buttigieg said in Council Bluffs recently, “this state could help us make history one more time.”
Ms. Jarrett said the importance of Iowa should be viewed through a broader lens. For Mr. Obama, it did not change the minds of black voters, but provided a stamp of legitimacy that was important for a first-time presidential candidate. In other races, including in 2004 when Senator John Kerry of Massachusetts won the Democratic primary, Iowa has been a springboard for the eventual nominee.
“There were people looking for early signals that he was a competitive candidate,” Ms. Jarrett said of Mr. Obama.
She also said campaigns should take other lessons from Mr. Obama’s success, including his campaign’s reliance on grass-roots organizing, digital advertising tools and modern voter targeting. She also said Mr. Obama’s campaign had financial resources to sustain the operation — a luxury some candidates this cycle had not had.
“Ultimately, it’s a combination of strategies,” Ms. Jarrett said. “Being able to raise money is important as well, and you can’t support a field organization if you don’t have the money.”
In South Carolina last week, at an event held by the Democratic Women’s Council of Darlington County, voters expressed an openness to voting for someone other than Mr. Biden. But they were looking to be wooed, by a candidate and a message that spoke directly to their concerns — not someone who had proven the ability to “win” by succeeding in Iowa.
“This is on the individual person,” Caroline Hannatt, 67, said. “Why is Iowa so important? Iowa doesn’t have any bearing on who I vote for.”
Jannie Lathan, a 69-year-old member of the same group, said as an overwhelmingly white state, the priorities of Iowa Democrats were not the same as South Carolina ones.
“I’ll stick with the criteria I laid out,” Ms. Lathan said.
“This is about our issues,” she added, meaning black people. “Not about who’s popular in the moment — but our issues.”