MICHEL MARTIN, HOST:

So this is it, the final week before voting begins in the 2016 presidential race. We're talking about the Iowa caucuses, which are held by both Republicans and Democrats a week from tomorrow, so candidates are all over the state right now. But it turns outs that winning Iowa isn't everything. Candidates who've lost this first round of voting have gone on to win their party's nomination, so don't be shocked if you hear candidates playing down this contest so a loss in Iowa doesn't seem quite so bad. NPR senior editor and correspondent Ron Elving has spent a lot of time in Iowa himself over the years, but he's with us now. Hi, Ron.

RON ELVING, BYLINE: Hey, Michel.

MARTIN: So let's start with Republicans. You know, the heart of Senator Ted Cruz's support has been among evangelicals in Iowa. And he had been edging out Donald Trump in some polls, but it appears now that Trump is regaining his edge in Iowa. So is Ted Cruz really in trouble there?

ELVING: Both are betting big on winning Iowa, and either one of them is going to suffer a real setback there because they've let their expectations be so high. Now it's tougher for Ted Cruz though because the situation is that he's well behind in New Hampshire, the next state that votes on February 9. So he really needs Iowa.

MARTIN: What about the Democrats? Hillary Clinton got the endorsement of The Des Moines Register yesterday, but, you know, it turns out that the paper has never endorsed a Democrat who's actually won the caucuses. And it turns out that Bernie Sanders seems to be posing a real threat to Hillary Clinton. So how is she kind of handling all this right now?

ELVING: She's been at it for weeks, tamping down the expectations that were so high for her earlier, especially in Iowa where she was assumed to be winning. So we can expect her to keep hammering away at electability, asking people to be realistic about who they put in the Oval Office. And hey, you know, with respect to that endorsement by The Des Moines Register, they have gone with underdogs pretty consistently among the Democrats - John Edwards, Bill Bradley, Paul Simon. And the pattern's been that those candidates then do better than they were expected to before the endorsement of the Register, so let's bear that in mind. It's probably a net-plus for Hillary.

MARTIN: On the other side of the question, speaking about The Des Moines Register, Marco Rubio was the Republican that The Des Moines Register endorsed. You know, it's hard to say. It just happened last night. But how is that affecting him at this point?

ELVING: You know, it hasn't done much for Republicans in the past to have the Register's endorsement. Probably a bigger plus for him is that Joni Ernst is not endorsing, but at least campaigning with him right now. She is the very popular freshman senator from Iowa, Republican. And it also helps Rubio a lot that he's the third option to Trump and Cruz. You have a big Republican wave of office-holders all over the country trashing Ted Cruz, saying it can't be him while meanwhile, the conservative media, on talk radio and the blogs, are telling people oh, it can't be Trump. He's not a true conservative. So Rubio is in there to go three, two, one - third place in Iowa, second in New Hampshire and then a big leap to win South Carolina. That might be a bridge too far, but that's the plan.

MARTIN: So is Marco Rubio, the Florida senator, emerging as the hope of the establishment? Or is there another candidate that they like and seem to be rallying behind?

ELVING: The establishment hasn't been able to make up its mind. But in New Hampshire, the guy who's rising fastest is John Kasich. And he spent more money in New Hampshire than anyone but Jeb Bush, and in his case - Kasich's case - that money is actually seeming (laughter) to do him some good. He's a good fit for the Granite State conservatives, and we expect to see him battling Rubio and Cruz for the second place spot there in New Hampshire, especially if Rubio doesn't get the momentum out of Iowa that he's hoping for.

MARTIN: That's NPR's Ron Elving. Thank you, Ron.

ELVING: Thank you, Michel. Transcript provided by NPR, Copyright NPR.