Even as the public remains closely divided about his presidency, Barack Obama is holding on to his support from the so-called “Obama coalition” of minorities, liberals and young Americans, an Associated Press-GfK poll shows, creating an incentive for the next Democratic presidential nominee to stick with him and his policies.Hillary Rodham Clinton, by comparison, is viewed somewhat less favorably by the key voting groups whose record-setting turnout in 2008 propelled Obama to the White House and will be crucial to her own success. Roughly two-thirds of Hispanics view Obama favorably, compared to just over half of Hispanics who say the...