AUDIE CORNISH, HOST:
Republicans and Democrats in Indiana vote for presidential candidates today, and to explain what's the - what this race means in a national context, we're joined by Mara Liasson, NPR's national political correspondent. And Mara, to start, why has Indiana become such an important state for the Republicans in particular?
MARA LIASSON, BYLINE: This is the last stand of the stop-Trump movement. If Trump performs in Indiana as he's been polling and wins pretty big, that will probably dry up the money behind the stop-Trump movement, and it will be a huge psychological blow to Ted Cruz. Cruz has said Indiana is do or die for him, but he's also said, I'm in it for the distance.
Now, both of those things can't be true. It doesn't necessarily mean that Cruz will drop out, but for Cruz, the goal of stopping Trump from getting 1,237 delegates before the convention - that dream will probably die if he can't win Indiana tonight because Trump is just simply so close to the number.
CORNISH: And in the meantime, there's been this really strange dustup between Donald Trump and Ted Cruz where Trump essentially repeated and unfounded, unverified National Enquirer story that suggests, of all things, that Ted Cruz's father might have known JFK's assassin. Now, what do you make of Trump picking up this line of attack?
LIASSON: Well, this is really extraordinary. Trump calls himself the presumptive nominee. He's been talking about unifying the party. He almost has the nomination sewed up. So why not be magnanimous and conciliatory? He brought up the story unprompted, took it as total truth, suggested that Ted Cruz's father somehow was involved with Lee Harvey Oswald.
And why would he do that on a day - on a week when so many parts of the Republican establishment are accepting his inevitability? They're coming to accept him as the nominee, talking about, now is the time to unite the party. So why would he do this?
CORNISH: What are the running theories?
LIASSON: One explanation is he just can't help himself. But it does suggest that the general election is going to be like this. He's talked a lot about pivoting to being more presidential, but he hasn't actually done that. And the question is, will Hillary Clinton respond the way that Ted Cruz did today by saying that Trump was amoral and a pathological liar and a serial philanderer? Or will she find another way of responding to him and making the contrast?
CORNISH: Speaking of Hillary Clinton, what could happen today in Indiana's Democratic race?
LIASSON: Her campaign has been downplaying Indiana, suggesting that she very well might lose there. If Bernie Sanders wins Indiana, he gets a little bit of oxygen. He gets to say he has some momentum. But he doesn't get to change the math. Hillary Clinton could lose all of the remaining contests by 20 points, including tonight's, and still win the nomination.
CORNISH: Right. She's already moved on from Indiana (laughter), and she's campaigned in West Virginia today. And that's a state that Democrats have very little reason to hope for in the general election. Am I right about that? I mean, why is she there?
LIASSON: Well, she's there for three reasons. First of all, there are upcoming primaries in West Virginia and in Kentucky, and she also on this trip went into the coal country part of Ohio, which is a big battleground state.
And she is trying - and the third reason is that she's trying to correct the record about a very unfortunate statement she made previously where she said, we're going to put a lot of coal miners out of work. She said that that was taken out of context. But she made a speech in Athens, Ohio, today where she offered a very heartfelt mea culpa.
She said she wanted to come to this region where Democrats don't do very well to say directly to the people of Appalachia that she doesn't disrespect them, that she will fight for their families even if they don't vote for her and that she wouldn't overpromise but that she'd would work hard to make sure that people everywhere, including Appalachia, have a chance to get jobs that pay enough to stay in the middle class, to create strong communities that you can grow up in and grow old in. And this was a warmer, more authentic Hillary Clinton than we've seen recently and may be the beginning of a pivot to a more effective general election message.
CORNISH: That's NPR's Mara Liasson. Thank you so much.
LIASSON: Thank you. Transcript provided by NPR, Copyright NPR.