Democratic U.S. presidential candidate and U.S. Senator Bernie Sanders speaks at the NBC News - YouTube Democratic presidential candidates debate in Charleston, South Carolina January 17, 2016. REUTERS/Randall Hill

Sen. Bernie Sanders's answer tonight to the question about how he plans to win the Democratic nomination with such low poll numbers among black voters suggests his campaign still lacks a strategy to appeal to one of the party's largest and most loyal voting blocs.

The Vermont senator boasted that when he started his campaign he was polling in the low single digits, but he has now pulled even with or ahead of Hillary Clinton in the early states of Iowa and New Hampshire. The populations of both those states are overwhelmingly white, as is Vermont, where Sanders has held elected office for three decades.

The debate is being held in South Carolina, where African Americans are more than half of the Democratic electorate. Polls from the fall showed Sanders lagging badly in the Palmetto State, which holds its primary Feb. 27. In November a poll by Winthtrop University reported:

Clinton was the choice of 71 percent of likely Democratic voters ... Sanders received 15 percent support, and former Maryland Gov. Martin O'Malley got 2 percent. Among black voters, who make up more than half of South Carolina's Democratic primary voters, Clinton's lead was bigger — 80 percent to 8 percent for Sanders.

During the past few days, Clinton's campaign held numerous campaign events aimed at energizing black voters. On Saturday, several black members of Congress visited barber shops and beauty shops around Charleston to push Clinton's candidacy and on Sunday they attended numerous churches to represent her. Former attorney general Eric Holder also campaigned with Clinton over the weekend.

The three Democratic presidential contenders engaged in heated exchanges on health care, gun control, former president Bill Clinton and other issues in Charleston, S.C. on Jan. 17. Here are the key moments from the two-hour debate in three minutes. (Sarah Parnass/The Washington Post)

Sanders had some high profile supporters in town, too. Noted scholar Cornel West was a popular figure at South Carolina Democratic Party events, including a dinner and fish fry held Saturday night. Stephen Bishop, an actor who is most recently know for his role in the BET drama "Being Mary Jane," also attended events on Sanders's behalf, including emceeing a debate watch party Sunday night. Rep. Keith Ellison (D-Minn.), perhaps the only member of the Congressional Black Caucus to endorse Sanders so far, also stumped for Sanders in Charleston. Atlanta rapper Killer Mike was in town and, along with Sanders, West and former Ohio state senator Nina Turner, took part in a live-streamed discussion about the legacy of Dr. Martin Luther King Jr.

Still, most of the people at Democratic Party events sporting Sanders buttons and t-shirts were young white people. Sanders and his supporters continue to give the same response when asked what it will take to improve his standing among black voters. And he repeated it Sunday night: "When the African American community becomes familiar with my congressional record and my agenda, just as the general population has become more supportive, so will the African American community, so will the Latino community. We're on the path to victory," he said.