ROBERTS: It gives Trump ammunition. And he's been setting her up for this for months. I mean, back in January he started saying that she didn't have the strength and stamina to be president. And he knew at some point in the campaign schedule that she, like all candidates, would get exhausted. But the fact that it comes now, when the polls are tightening and Democrats were already saying that Hillary was the only candidate who could not beat Trump, and it's taking her off the campaign trail, canceling her trip to California today, it has them very nervously beginning to whisper about having her step aside and finding another candidate.

GREENE: That is no small thing to say. Is that a real thing? Or is this just some nerves after a weekend of —

ROBERTS: No, I think it's unlikely to be a real thing. I'm sure it's an overreaction of an already skittish party. But, you know, they have looked at what happens in that circumstance. The Democratic National Committee chair convenes the committee, and they vote. Now ironically the candidate that everybody looks at is Joe Biden, who of course is older than Hillary Clinton, but then again so is Donald Trump, and we know nothing about his health.

GREENE: But I guess important to say, though, there is no indication — I mean, the Clinton campaign has said that she is fine and, I mean, is going to resume her schedule.

ROBERTS: Absolutely, and that is happening, we assume. But there is enough unhappiness that this kind of sotto voce stuff is going on.