NORTH CHARLESTON, S.C. — After activists with Black Lives Matter disrupted his campaign appearances this summer, Senator Bernie Sanders, the surging if still long-shot candidate for the Democratic presidential nomination, added a new section to his hour-plus stump speech, explicitly addressing racial injustice.

But the true measure of the success of those remarks will not be just defusing anger but reaching out to African-American voters, who are an essential bloc within the Democratic Party — especially in South Carolina, an early primary state, throughout which Mr. Sanders campaigned on Friday and Saturday.

Because black votes matter, too.

Meeting with about 50 pastors and community leaders, most of them black, at the Springfield Baptist Church in Greenville on Friday afternoon, he argued that income inequality was the moral issue of our time and that the people it hurt most were African-Americans. He said that the criminal justice system should be reformed and that the killing of nine black people at Emanuel A.M.E. Church in Charleston — a massacre that had caused him to reschedule a planned campaign visit at the time — made it clear that the government needed to do more to break up hate groups. He made a similar stop on Saturday in Orangeburg.

But while Mr. Sanders went out of his way at both stops to reach out to black leaders, the thousands of people who came to hear him bellow, “We are going to end institutional racism,” as he did here on Saturday night, were overwhelmingly white.