Joe Biden takes his time in deciding on a 2016 presidential run

Julian Zelizer, a presidential historian at Princeton University, argued Biden can speak to middle class concerns more fluently than Clinton, who has at times struggled to project the kind of populism that comes naturally to the vice president. "He's in some ways very much a New Deal Democrat who's concerned about what the government does to help the middle class," Zelizer explained. "I don't think it's hard for him to talk about this. This is who he is."