Perhaps most important is the group that voted in much larger numbers than in 2012: white voters without a college degree. (Trump won this bloc 63 percent to 32 percent.) Generally speaking, college graduates are more likely to vote than non-college graduates, even when controlling for race. According to the Current Population Survey, whites without a college degree made up 44 percent of voters who cast a ballot in 2012, and 58 percent of registered voters who didn’t vote.
…Registered voters who didn’t vote on Election Day in November were more Democratic-leaning than the registered voters who turned out, according to a post-election poll from SurveyMonkey, shared with FiveThirtyEight. In fact, Donald Trump probably would have lost to Hillary Clinton had Republican- and Democratic-leaning registered voters cast ballots at equal rates.
…The biggest reason given by non-voters for staying home was that they didn’t like the candidates.2 Clinton and Trump both had favorable ratings in the low 30s among registered voters who didn’t cast a ballot — both had ratings in the low 40s among those who did vote. That’s a pretty sizable difference. So why was Clinton hurt more by non-voters? Trump was able to win, in large part, because voters who disliked both candidates favored him in big numbers, according to the exit polls. Clinton, apparently, couldn’t get those who disliked both candidates — and who may have been more favorably disposed to her candidacy — to turn out and vote.