Well, we had a bunch of primaries and caucuses on the Democratic side. Bernie Sanders won the Nebraska and Kansas caucuses. That keeps his campaign alive. But Hillary Clinton won Louisiana, which was the big prize of the night, so she ended up winning more delegates than he did yesterday.

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

If [Hillary] Clinton wins, history will also be made: She would be the first female U.S. president, of course, but also the only candidate in the modern era, other than George H.W. Bush, who managed to follow a two-term president of her own party.

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.

Obama has built his public image around his ability to bridge divisions - racial, ideological or generational. And that was his reputation, even at Harvard Law School, where he was the first black president of the 'Law Review.

After months and months at the top of the polls, there is a real possibility that Donald Trump could be the nominee.

Well, it's possible that the new infusion of ad money against Donald Trump kept his margins in Kentucky and Louisiana down a bit. But we're also seeing something that we've never seen in 100 years, which is we are seeing the crackup of a major American political party.