NOEL KING, HOST:
Tonight in Iowa, six Democrats who are running for president will debate. It's the last debate before the Iowa caucuses, at which point voters start to decide. NPR's Danielle Kurtzleben is in Des Moines. Hey, Danielle.
DANIELLE KURTZLEBEN, BYLINE: Good morning.
KING: So what's the mood there? Are people amped to caucus?
KURTZLEBEN: Yes, which is not unusual ahead of the caucuses. It's cliche at this point, but Iowans do take this very seriously. And Iowa Democrats are very fired up about their given candidates. But you know, the other thing I would say is they're also nervous because - we've been hearing about electability - any given one of them wants to pick the right candidate to defeat Donald Trump. And a lot of the ones I've asked have said, you know, it's hard to be certain that any given candidate is that candidate.
KING: And this is probably the reason that, at this moment, there is not a clear front-runner, is there?
KURTZLEBEN: No. Here in Iowa, any given poll you look at these days, it has those four people bunched at the top of the pack - Vermont Senator Bernie Sanders, former Vice President Joe Biden, Senator Elizabeth Warren and former South Bend Mayor Pete Buttigieg. They've all traded the leads throughout this race - at least here in Iowa, they have.
But no, no one is - really comes out quite on top here. You know, Sanders and Biden have their high name recognition. They have remained strong. Warren and Buttigieg, they are highly organized. They have a lot of staff here, which might not sound important. But that is important because it could help them turn out people on caucus night, which is, of course, a big deal.
KING: The thing you got to do, right. We're...
KING: ...Hearing, Danielle, that the tone has gotten sharper among the candidates in the past couple of days. What are they fundamentally disagreeing over?
KURTZLEBEN: Well, you have a few topics. Take your pick, you know?
KING: (Laughter) OK.
KURTZLEBEN: This has popped up on a few fronts. Right? I mean - so first of all, here's one front. You have Sanders supporters and surrogates who have gone on the attack against Warren and Biden in particular. Now, against Biden, they're not necessarily new attacks, but they're more aggressive. What they've been going after him on first of all is his vote to approve the war in Iraq. Especially given the situation in the Middle East now...
KURTZLEBEN: ...It's sort of brought up new opportunities - right - to attack Biden for that. And by the way, if you're feeling deja vu, it's because, at this point, the Iraq War has come to define Democratic primaries. Think about it. It's happened in 2004, 2008. 2016, it came up again. Now it's coming up again, which shows just the lasting impact. Of course, it was an unpopular war - at this point, very unpopular. And so this does keep coming up as long as there are people in these races who voted for or against it.
Aside from that, Bernie Sanders' campaign co-chair Nina Turner, she wrote an op-ed in a South Carolina newspaper this weekend saying that, essentially, Joe Biden is not - has not delivered for black voters but that Bernie Sanders can. Now, of course, that comes as a poll recently came out from the Washington Post and Ipsos saying that Joe Biden is doing very well with black voters at 48%. Bernie Sanders was well behind that.
KING: OK. So some of these things are about policy; some of them are about electability. And then there's some stuff that's a bit more personal. Up until this point, Bernie Sanders and Elizabeth Warren have avoided direct conflict. But then that has changed, hasn't it?
KURTZLEBEN: Yes, most definitely. We saw that come up on two fronts over the last few days. Politico first reported over the weekend saying that Sanders volunteers were using this script saying that she can't really expand the base that she mostly appeals to - highly educated voters, for example. She responded saying she was disappointed.
Then we had this leaked story yesterday about a private 2018 meeting where - in which Sanders allegedly said that a woman can't win in 2020. Now, the sourcing was anonymous, but two of the people were linked to the Warren - they talked to Warren after that meeting. Now, Sanders has denied this, but this has become another thing that has really blown up. So both Sanders and Warren will probably be asked about that tonight at the debate. We'll see what they say.
KING: Yeah. NPR's Danielle Kurtzleben in Des Moines. Thanks, Danielle.
KURTZLEBEN: Yes, thank you. Transcript provided by NPR, Copyright NPR.