AUDIE CORNISH, HOST:
Tonight's the night when voters finally take the spotlight in the 2016 presidential contest. Voters in Iowa will file into schools, community centers, libraries and even living rooms to speak up for their candidates. NPR national political correspondent Mara Liasson is here to talk about what tonight may mean for these campaigns. Hey there, Mara.
MARA LIASSON, BYLINE: Hi, Audie.
CORNISH: OK, so potentially significant headlines that could come out of Iowa tonight - what do you think?
LIASSON: Here my three. Trump is for real. Trump is a loser. And the third one is, Bernie wins. Now, you can see two of the headlines were about Trump.
LIASSON: But they were for opposite outcomes, but that's because everything about his campaign has been completely unexpected. The big question about him was could he turn his supporters - and there are a lot of them - into actual voters? We wouldn't ask this question about a normal, ordinary candidate, but because he's been so unorthodox, that's been a big question. And then the Trump is a loser - Trump's whole campaign is based on winning everything - every poll, every debate. Everything is the biggest, best, most fantastic. If he loses Iowa, he's a loser. How will he react to that? And the third headline, Bernie wins - Bernie Sanders beating Hillary Clinton would be an upset. That's unexpected, and that would be big news.
CORNISH: Let's talk about the factors that could make those headlines come true or not. What are you actually watching for this evening?
LIASSON: The biggest factor is turnout. Most analysts believe that a big turnout benefits the two outsiders - Donald Trump and Bernie Sanders. Lower turnout would help Ted Cruz and Hillary Clinton. And both Sanders and Trump have been trying to expand the universe of Iowa voters by bringing in people who've never caucused before. Trump wants to big in those non-college-educated, white, working-class voters who line up for hours to get into his events, and Sanders has been reaching out to young voters.
Both these candidates lead by double digits with people who say they're participating in their first caucus, but the big question is how many of those first-time Trump and Sanders voters or potential first-time voters will actually turn out.
CORNISH: OK. Those are the sort of big names for you. Can we dig in a little more on the Democratic side in terms of what matters most?
LIASSON: Well, the Democratic side really is a battle between organization and enthusiasm. Both candidates have enthusiastic supporters. Both have good organization. But Hillary Clinton is relying more on a ground game. Bernie Sanders is relying more on the raw passion that he's been able to be excite among his supporters.
And Hillary Clinton, who was stung by her third-place finish eight years ago in Iowa, has built a very formidable operation. She started organizing very, very early. Bernie Sanders came later, but he has concentrated on an organization in college towns where his supporters are and recently trying to move into rural areas because geography also really matters for Democrats. Unlike the Republican caucuses, Democrats report delegate totals not vote totals, and delegates are awarded through a formula based on how candidates do in precincts all over the state. And that means Sanders could be at a disadvantage if his support is heavily concentrated in college towns and urban areas.
CORNISH: All right. It gets complicated there.
CORNISH: Can you talk more about the Republican side? What would make the most difference in that contest?
LIASSON: Well, I think the big question is, can Ted Cruz win Iowa? I think the stakes are highest for him. This is a state tailor-made for Ted Cruz - lots of conservative evangelical voters. If he comes in second to Trump in Iowa, he's going to have a much harder path to the nomination. That's why Cruz has been telling his supporters that if Trump wins Iowa, he will be unstoppable because Trump doesn't need to win Iowa to get the nomination because he's ahead in all the other early states. I also am watching to see how Marco Rubio does. Does he come in a strong third, or does he really surpass expectations and surge past Cruz to place second? In which case he would become, I think, the clear establishment alternative to Trump or Cruz.
CORNISH: And that's NPR's national political correspondent Mara Liasson. Mara, thanks.
LIASSON: Thank you. Transcript provided by NPR, Copyright NPR.