More broadly, in interviews with African-Americans across the state this past week, many said they were eager to send a message to the national Democratic Party: that their views on electability — which candidate is best suited to beat President Trump — would not be shaped by outcomes in the predominantly white states Iowa and New Hampshire, which backed former Mayor Pete Buttigieg and Senator Bernie Sanders in contests earlier in February.

“We’re the base, and we’re yet to express ourselves,” said David Cakley, a church deacon from Goose Creek, S.C, referring to black voters. “Biden needs a boost and we’re going to give it to him.”

Mayor Stephen K. Benjamin of Columbia, S.C., who has endorsed the former New York City mayor Michael R. Bloomberg, summed up the urgency for black voters in this primary by quoting a line from the Atlanta rapper André 3000: “The South got something to say.”