The working class in the USA has been abandoned by Republicans and most Democrats, not by president Obama, but yes by president Bill Clinton (D-Senators Harkin and Sanders agree). Hillary's ties to Bill were a big negative. And too, the exit polls for 2016 and 2012 don't show a more racially polarized electorate for our recent election. Trump got more of the Hispanic vote and the African-American vote than Romney did in the last election.
In 2012 Obama got 39% of the White vote.
In 2016 Hillary got 37% of the White vote.
In 2012 Romney got 27% of the Hispanic vote.
In 2016 Trump got 29% of the Hispanic vote.
In 2012 Obama got 93% of the African-American vote and Romney got 6%.
In 2016 Hillary got 88% of the African-American vote and Trump got 8%.