Clinton also plans to intensify her focus on issues of importance to minority voters, such as immigration, civil rights and gun control, dispatching African-American supporters to make her case and launching a flurry of attacks to undermine any credibility Sanders may be building within the black community. Focus-group surveys conducted by Clinton's campaign with undecided black voters in Charleston found that the former secretary of state has retained a high degree of trust with African-Americans, even as her numbers on trust and honesty have declined overall, according to Clinton aides. An NBC News/Wall Street Journal/Marist Poll in late January showed African-American voters said they preferred Clinton to Sanders, 74 percent to 17 percent Since New Hampshire, Clinton has launched a full-scale press, unveiling endorsements from top African-American leaders. [...] Clinton supporters are targeting Sanders' record on issues like racial equality and criminal justice, even playing down his early support for the civil rights movement as a college student who joined the 1963 March on Washington. On Wednesday, he held a heavily publicized breakfast with civil rights activist Al Sharpton in Harlem, and Ta-Nehisi Coates, an influential writer on racial issues, said he would vote for Sanders.