NORTH CHARLESTON, S.C. -- Joe Biden went to the Royal Missionary Baptist Church in South Carolina in late February, before the state's presidential primary, and listened as the Rev. Isaac J. Holt Jr. delivered a message of encouragement."You're going to win," Holt said he told Biden privately, a political prophecy that was fulfilled in the coming days.Sign up for The Morning newsletter from the New York TimesNow Holt, the pastor of one of Charleston's largest Black congregations, has another message for Biden as he plans for his incoming administration: "Biden owes us. And we have not forgotten."Black voters have a political marriage of convenience with the Democratic Party. They are at once the party's most solid voting demographic and deeply frustrated by the lack of systemic change its politicians have delivered for them.In South Carolina, the state that helped propel Biden to the Democratic nomination and where about half the Democratic electorate is Black, voters complain of receiving campaign promises from politicians while they are running but not being prioritized once they are elected.There are similar grievances among voters in cities like Milwaukee, Detroit and Philadelphia -- hubs of general-election campaigning in key swing states -- who have grown used to the silence that follows presidential election years.In their telling, attention quickly shifts to midterm races in gerrymandered, Republican-leaning congressional districts, and the Black voters who helped Democrats ascend to the White House are sometimes discarded. Their issues are too divisive. Their needs are too great.Biden has insisted that this time will be different, and people like Holt are taking him at his word. Last month, in his victory speech after becoming president-elect, Biden cited Black voters specifically, alluding to those who rallied around him in South Carolina after his primary campaign flopped in other early-voting states."Especially at those moments when this campaign was at its lowest ebb, the African American community stood up again for me," Biden said. "You've always had my back, and I'll have yours."But who defines political priorities for Black voters, and what does it mean to have their back?Leading Black politicians, civil rights leaders, activists and many of the same South Carolina church leaders Biden leaned on to turn his campaign around all said in interviews that it was important to address the coronavirus pandemic. But they also raised issues that ran the gamut of liberal policy initiatives, from investing in small businesses and historically Black colleges and universities to tackling student debt and climate change.Many also pushed back against the singular focus on racial representation that has dominated debates over Biden's transition team and Cabinet picks. Having a Cabinet that reflects the racial diversity of America is good, they said. But they added that Biden's legacy on race would be judged on his willingness to pursue policy changes that address systemic racism -- a standard he has set for himself."