AUDIE CORNISH, HOST:
President Obama is poised to make the case that Hillary Clinton should be the one to succeed him in the White House. The president is the headliner tonight here at the Democratic National Convention. The long list of speakers also includes Vice President Joe Biden and Clinton's vice presidential running mate, Virginia Senator Tim Kaine.
Now, here to give us a preview of the evening is NPR national political correspondent Mara Liasson. And Mara, let's start with President Obama. What is his mission tonight?
MARA LIASSON, BYLINE: He has a very big job tonight. This is kind of a valedictory speech for him. It's probably his last biggest audience, and he has as much riding on the outcome of this election as Hillary Clinton does because his legacy is on the line. If Clinton's elected, his agenda continues. If it's President Trump, his agenda will be dismantled or at least unraveled.
So I think tonight you'll hear him not only provide another character witness for Clinton - say she's tough and qualified and tenacious. I also think you'll hear him giving an accounting of his own record because he's been doing that in many recent speeches, talking about what things were like eight years ago compared to today.
But what I'm watching for is how much the speech is about him and his record. How much is it about her, and how much is it about Donald Trump because on the campaign trail, the president has shown he is eager to take the fight to Trump and to frame this election as a contest about values. What kind of country do we want to be?
CORNISH: Meanwhile, national security is the theme of the night, something we haven't heard talked about too much so far. Now, as the former secretary of state, Hillary Clinton has a national security record, which can cut both ways.
LIASSON: This is one of the many balancing acts the campaign has to do here. How do they talk about foreign policy, about her achievements when voters look around the world and it looks like the world is falling apart - new terrorist attacks in Europe every day, and the world's only super power seems powerless to do anything about it except for get involved in endless stupid wars.
So she - and the other problem is that she has an opponent who's both bellicose and isolationist at the same time. He might not defend NATO allies, but he'll also bomb the expletive deleted out of ISIS. That's a tough needle to thread.
CORNISH: Part of what Bill Clinton and others have been trying to do here is reintroduce Hillary Clinton to the American people who have known her for more than two decades. How's that going so far?
LIASSON: Inside the hall, I think it's going great. Outside the hall, we don't know yet. It's very hard to reinvent or reintroduce someone who's been on the scene for so long and has such a well-defined image and has such high unfavorable ratings. Currently she is as unpopular or seen as unfavorably as Donald Trump. She might be the most famous person that no one knows, but that's not really true.
Last night her husband, in a very artful speech, said that the Hillary people think they know is a cartoon character created by the Republicans. And the question for the Democrats here in Philadelphia is, is that cartoon indelible or erasable?
CORNISH: Meanwhile Clinton has, like, all these people speaking on her behalf, but I understand that not all of these surrogates have worked out for the best (laughter).
LIASSON: (Laughter) No. This goes under the - with friends like these, who needs enemies - department. Terry McAuliffe, her great friend, former DNC chair and fundraiser extraordinaire yesterday said after the election, oh, she might agree to the TPP trade deal after all.
Well, her campaign leapt into action, immediately said, no way, she opposes it before the election and after the election full stop. But they still didn't agree to Bernie Sanders' demand for the platform to say there should be no vote ever on TPP in the Senate, and Terry McAuliffe's screw up just makes Bernie Sanders' supporters even more suspicious of her.
CORNISH: That was literally one of the most protested aspects of the platform this week.
LIASSON: Yes, yes, yes.
CORNISH: That's NPR's Mara Liasson with me in the Wells Fargo Center in Philadelphia. Thanks so much, Mara.
LIASSON: Thank you. Transcript provided by NPR, Copyright NPR.