The [Hillary] Clinton campaign's recent travel schedule shows how seriously it takes this problem. She and her surrogates have held rallies in cities like Philadelphia, Detroit and Cleveland, trying to boost turnout among African-Americans.

[Hillary] Clinton has also struggled with key groups of voters.

You have [Donald] Trump and [Ted] Cruz battling it out, and the moderate establishment candidates like Chris Christie or Jeb Bush, Marco Rubio, John Kasich - they have formed a circular firing squad.

A big win for [Hillary] Clinton would allow her to claim that the country rejected Trumpism, while a narrow win leaves her limping into office with the highest unfavorable ratings for any new president.

I think that's why we see this mixed reaction - Republican congressional leaders like Paul Ryan speaking out very firmly, but Republican candidates not as much, with the exception of the candidates in the single digits like Jeb Bush or Lindsey Graham, who said how to make America great again tell - Donald Trump to go to hell.

Until he announced his immigration policy last week, Obama had the support of most Hispanic voters - but not the enthusiasm they had shown for him in 2008. That may be changing in part because of the decision not to deport young immigrants whose undocumented parents brought them here as children.

The base has chosen or is choosing a candidate that the establishment says is absolutely unacceptable. And what that means is this marriage of an elite, big business-backed establishment and a blue-collar, downwardly mobile base has really come to a divorce.