Answering Sanders's criticisms over her ties to Wall Street, Clinton told the Charleston, S.C., audience, that he has "criticized President Obama for taking donations from Wall Street. Sen. Sanders called [Obama] weak, disappointing; he even in 2011 publicly sought someone to run in a primary against President Obama."
That charge was originally used by the third Democratic presidential candidate, Martin O'Malley, in an earlier debate, and fact-checkers judged it half-true, because Sanders had suggested it would be a good thing leading into the 2012 election to have a primary challenger pressuring Obama from the left.
Clinton's accusation of disloyalty against the first African-American president could have particular resonance in South Carolina, where a large proportion of the Democratic electorate will be black.
Sanders rebuked the charge, saying that he and Obama "are friends." 
"We've worked together on many issues."
Sanders said he campaigned hard for Obama in both 2008 and to see that Obama got reelected in 2012.