Asked why Senator Bernie Sanders of Vermont lost decisively to Mr. Biden among black voters in recent races for the Democratic presidential nomination, Mr. de Blasio suggested those voters did not know enough about Mr. Biden — remarks that some called offensive and condescending.
“It stands to reason if people have a certain amount of information — and I don’t blame them for this, I understand it,” Mr. de Blasio said on the MSNBC show “Morning Joe,” before a host, Elise Jordan, interrupted.
“So you’re saying they were low information?” she asked.
“No, no, no,” said Mr. de Blasio, who endorsed Mr. Sanders in February. “I’m saying you had a whole lot of candidates, which I think is a very different discussion. The information that I think people received about Joe Biden was some of his historic connection, which, understandably, means something to people.”
“Of course,” the mayor said.
Mr. de Blasio said that a “one-on-one race brings out a whole different set of information,” and that Mr. Biden’s record was not thoroughly examined among a crowded field of candidates.
In a statement on Friday, Mr. de Blasio said that Mr. Biden hadn’t been vetted and that the focus had been on other candidates. “Now with a one-on-one, you’re going to get a really intensive examination of Joe Biden, and I think voters of all different backgrounds are going to see a lot more information,” he said. “I think it’s going to affect their thinking. That’s what I was trying to say.”
Many on social media called his initial remarks insulting. “I think black voters knew enough about both of them to say which one they were interested in,” said Melanye Price, a professor of political science at Prairie View A&M University.
The idea that, having more information, black voters would go with Mr. Sanders is “condescending,” she said.
Davin Phoenix, an associate professor of political science at the University of California, Irvine, said that the notion that black voters were not aware of Mr. Biden’s record reflects a “fundamental lack of comprehension of how black voters generally navigate politics.”
“African-Americans rarely, if ever, have the luxury of choosing candidates who they perceive as perfectly, or even adequately, aligned with their preferences, or fully committed to advancing the interests of the group,” Professor Phoenix said.
However, it is important to African-Americans that Mr. Biden served as Mr. Obama’s vice president. “Bernie Sanders knows it, too,” Professor Price said, “that’s why he’s now showing commercials with him and Obama.”
Mr. Biden won 10 states in the Super Tuesday primaries, and has nearly 500 delegates so far. Mr. Sanders, who has about 450 delegates, has acknowledged that he had “not done as well in bringing young people into the process” as he expected.
In Texas, where voters were predicted to favor Mr. Sanders, Mr. Biden earned his most significant win, giving him a large and unexpected share of Texas’ 228 pledged delegates in the third-biggest state in the Democratic primary. Mr. Biden had spent his final 24 hours before Super Tuesday campaigning in Houston and Dallas, two cities with large black populations and multiple congressional districts.
Mr. Sanders made similar comments about Mr. Biden’s success Wednesday on “The Rachel Maddow Show,” when asked about his weak track record with black voters in the South, this year and in the 2016 Democratic primary.
“We’re running against somebody who has touted his relationship with Barack Obama for eight years,” Mr. Sanders said. “Barack Obama is enormously popular in this country in general and the African-American community.”
After pointing to some polls indicating he was running ahead of Mr. Biden among African-American voters, Mr. Sanders said that “it’s not that I’m unpopular,” but that Mr. Biden was running with his “ties to Obama” and it was “working well.”
“It’s not enough to just be around those young millennial activists, who I think are very important, you have to have to actually go into some of these churches, go into some of these community centers and talk” with older black voters, she said.