White voters were 72 percent of the electorate in 2012, and their share of the population has shrunk a couple points since then. [Donald] Trump has had trouble winning certain segments of the white vote, such as suburban women and college-educated voters.

As one person said to me , Republicans know [Donald] Trump is a stain on their party.

Even if [Donald] Trump concedes, some of his supporters have promised to take up arms against [Hillary] Clinton.

The winner's margin of victory also matters. If it's a squeaker, that will make the lessons learned for both parties much murkier.

The establishment is divorcing itself from its base - from voters who are choosing a candidate who says he stands for things that are anathema to the establishment.

What if he says [Donald Trump] plans to run again in 2020?

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.