boston democratic white house candidate hillary clinton lead among likely voters age 18 29 accord harvard university opinion poll release wednesday former u.s. secretary state support 49 percent likely voters ahead republican rival donald trump 28 percent support substantially wide lead democratic president barack obama republican former massachusetts governor mitt romney point 2012. national poll voters age also show clinton lead though substantially narrow margin 14 percent respondents say plan vote libertarian gary johnson percent support green party jill stein 11 percent still undecided one three self-described johnson voters say likely change mind election day majority respondents 51 percent describe fearful future america 14 percent 2,150 respondents say believe country head right direction sense fearfulness predominant among white respondents though 85 black respondents say believe attack modern american society 62 percent respondents say believe race relations unite state would worsen trump elect president twenty-two percent think race relations would deteriorate clinton nov. election plurality 36 percent predict would stay survey conduct oct. 7-17 margin error 3.1 percentage point mean result could vary much either way clinton lead among young voters harvard poll find