AUDIE CORNISH, HOST:
The Democratic race for president is at a turning point as five more states on the East Coast hold their primaries today. Hillary Clinton is the clear front-runner. If she wins big tonight as polls suggest, her path to the nomination would look pretty clear. Her rival, Bernie Sanders, is likely to fight on no matter what, but even he is starting to acknowledge that the odds are getting long. NPR's Tamara Keith is in Philadelphia. Pennsylvania has more delegates at stake than in any other state tonight, right Tamara?
TAMARA KEITH, BYLINE: That's correct.
CORNISH: So what's on the line tonight for these candidates?
KEITH: At this point, Bernie Sanders is saying that he has a narrow path to the nomination. By our calculation, he needs to win all of these states today by about a 20-point margin in order to overtake Hillary Clinton in pledged delegates. Now, given recent polls, it's highly unlikely that he'd be able to do that, but it is entirely possible that he could win a couple of states or at least Rhode Island.
But the real challenge for him today is that all but one of the states voting has a closed primary. He does better in open primaries where independent voters can vote for - Democrats can vote for him. He does well with independent voters. But most of the primaries today are, only Democrats can vote in Democratic primaries.
CORNISH: So what has the Sanders campaign been saying will happen if things don't go well for them tonight?
KEITH: Well, a senior adviser to the campaign, Tad Devine, told The New York Times today that if Sanders doesn't hit his marks in these states, the campaign will tomorrow have to reassess his message. But Devine insists that Sanders will not drop out of the race, that he's going to continue through California and Washington, D.C., in June.
CORNISH: Help us read between the lines there. What does that mean - reassess his message?
KEITH: Well, it's not entirely clear what that would mean. It could mean possibly no longer talking about the path to the nomination as much because if he does do poorly tonight, it will be mathematically implausible for him to get there on pledged delegates.
But Sanders' wife, Jane, was on MSNBC this afternoon, and she even disputed the idea that there would be a reassessment of the message. Meanwhile, there was a fundraising email that came out that was very tough and also said that Sanders plans to keep fighting this all the way. Though he has certainly already - and it is likely to amplify under pressure to back off some of his strongest attacks against Clinton about her Wall Street speeches, for instance, as well as her campaign fundraising.
CORNISH: Meanwhile, there's been a lot of talk from Democrats about party unity in the past few days. But have there been any actual moves in that direction?
KEITH: (Laughter) Not exactly. The - Hillary Clinton and her surrogates are not calling for Sanders to get out of the race, but Clinton has started talking about 2008 when she lost the nominating fight and ultimately put her support behind President Obama - soon-to-be President Obama - and really encouraged her supporters, even the ones that said they just wouldn't support him, that had hard feelings about the primary - encouraged them to do that.
But Sanders' campaign is not at that point yet, certainly. In a fundraising - in that fundraising email I mentioned, they sent around a picture of the Clintons at Donald Trump's wedding. And last night, Sanders was asked in an MSNBC town hall about this, about party unity. And he said he can't snap his fingers and tell his supporters to support Clinton, that it will be incumbent on her to convince them that she really does deserve their support.
CORNISH: We'll be hearing elsewhere in the program about the Republican race. That's NPR's Tamara Keith in Philadelphia. Thanks, Tamara.
KEITH: You're welcome. Transcript provided by NPR, Copyright NPR.
