KELLY MCEVERS, HOST:

Now that Hillary Clinton has emerged as the clear leader in the Democratic primary race, the question for Bernie Sanders is this. Can he possibly stop her? NPR's Tamara Keith is following the Democratic race, and she is in New York City where Clinton is campaigning this evening. Hi there, Tam.

TAMARA KEITH, BYLINE: Hi, Kelly.

MCEVERS: It sounds like you're in a noisy place. Does Clinton feel like she's got this race locked up?

KEITH: Well, I mean, she still talks about wanting to work for every single vote, but her team is quite confident. Her campaign manager put out a memo today talking about the delegate math, saying that Hillary Clinton's lead over Bernie Sanders right now in terms of pledged delegates is bigger than the lead that President Obama had when he was Senator Obama campaigning against - bigger than his biggest lead. And because delegates are awarded proportionally, that means that Bernie Sanders would have to start winning not just a few states but all the states and by a fairly large margin in order to catch up.

MCEVERS: An yet, Bernie Sanders is not backing down. I mean, he was campaigning in Maine today, and the way he described his fight against Hillary Clinton hasn't changed, he says, because of yesterday's results. Let's listen.

(SOUNDBITE OF ARCHIVED RECORDING)

BERNIE SANDERS: We were up against the candidate supported by the entire political establishment, somebody almost universally known, someone who had been anointed as the inevitable nominee. Well, guess what? She's not so inevitable today.

(CHEERING)

MCEVERS: This is what Bernie Sanders says. What are his advisers saying about a real path forward?

KEITH: Well, they say that they believe he can make up the delegates by June just sort of chipping away at Hillary Clinton's delegate lead. Now, Sanders did not perform very well in Southern states with large African-American communities, and his campaign believes that he could do better with African-American voters in the Midwest. They're planning to hit Clinton on her support for trade deals - previous trade deals and her slow move to oppose the Trans-Pacific Partnership. They think that that might be able to help. They also say Super Tuesday was Clinton's best day on the calendar and that after this, they move into more friendly territory, including Maine, as you said, Kansas and Nebraska.

MCEVERS: So where else do we go from here in terms of the actual primary battle?

KEITH: Michigan - it's all about Michigan, and there's a debate in Michigan coming up this weekend. The Flint water crisis has played a large role in his campaign in particular because of Hillary Clinton's focus on it. Sanders' campaign is betting a lot on Michigan. They're saying that Michigan is the state where they can prove that he can win African-American voters.

And so all eyes will be on Michigan. Clinton's campaign says that on the same day, though, there's also a primary in Mississippi where Sanders isn't really trying to compete, so they say - again with the delegate math - by the end of that day, Clinton could actually come out with more delegates.

MCEVERS: That's NPR's Tamara Keith in New York where Hillary Clinton is campaigning this evening and where she is watching the Democratic campaign. Thanks so much, Tam.

KEITH: You're welcome. Transcript provided by NPR, Copyright NPR.