Hillary Clinton is also not a very exciting, inspiring candidate to a lot of the left-leaning Democratic base, especially in Iowa.

If Donald Trump wins, it will be a seismic event.

Romney still enjoys the Republicans' traditional advantage among voters who are veterans, but the Obama campaign is confident it can chip away at that.

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 enthusiasm for [Donald] Trump had gone up. The net result was it made people more supportive of him.

If [Hillary] Clinton can't boost African-American turnout, even with all that help, the question becomes whether she can make up for it with historic levels of support from Hispanics and suburban women.

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