“You go with what you know. A lot of black voters know Joe Biden,” said Michael Nutter, a former Philadelphia mayor and a current Democratic National Committee member who’s endorsed Biden. “There’s power in that and there’s loyalty in that.”

Sanders won a following among younger black voters during his 2016 run, when his progressive activism and criminal justice record fired up millennials of all races.

At least in the primary, Biden’s lead among older black Democrats is more consequential than Sanders’ edge among younger ones, because older voters typically vote in much greater numbers. That’s especially true in South Carolina, the first-in-the-South primary state where about 60 percent of the Democratic electorate is black. Polls show Biden is doing even better with African American voters there than he is nationally, giving him a potential crucial edge that he hopes to parlay into a string of victories throughout the Southeast and in big cities, where sizable chunks of the Democratic electorate are black.