ROBERT SIEGEL, HOST:
The presidential campaign reaches one of its major junctures tonight. Hillary Clinton and Donald Trump will meet for their first head-on debate. NPR's Mara Liasson is at Hofstra University on New York's Long Island where the debate will take place. Hello, Mara.
MARA LIASSON, BYLINE: Hi, Robert.
SIEGEL: And heading into the big matchup tonight, where does the race between Trump and Clinton stand?
LIASSON: The race is a dead heat. The polls have tightened mostly because Republicans are coalescing behind Trump and because Clinton is having trouble reassembling the Obama coalition of young people and minorities and women. Trump is even moving up in states he would need after you give him the big battleground states of Florida, Ohio, Nevada, North Carolina and Iowa.
Because Clinton has so many more paths to get to 270 electoral votes, Trump needs another state like Colorado or Pennsylvania. And new polls show that those two states are also tied. Colorado is a place where Clinton had pulled advertising because her campaign was so confident about winning it. So you can see how tight this race is.
SIEGEL: Let's talk about the campaign's objectives in this first debate tonight. What do the candidates need to accomplish?
LIASSON: Donald Trump needs to appear presidential. He needs to show a basic command of the facts. If there are two Trumps - the insult-comic Trump who dominated the primaries and then the teleprompter Trump who's been more disciplined and restrained recently - he needs to be the teleprompter Trump tonight. But of course there is no teleprompter for a 90-minute, no-commercial-break debate. He - his job really is to reassure voters who don't want to vote for Clinton but are worried about his temperament - he has to show them that he's a plausible president.
Clinton, on the other hand, has to show voters that she's honest, likeable, trustworthy. She has to undermine Trump and showcase an affirmative argument for herself all while appearing not too aggressive or any of the other things that reflect poorly on female candidates in debates. So in other words, her job is harder than doing everything Fred Astaire does only backwards and in heels.
LIASSON: But that long list really lays out Clinton's basic dilemma. She can't do it all. So I'm watching to see what she decides is her priority - laying out the affirmative case for herself or undermining him.
And the other thing we'll see tonight by these candidates' answers is who they think their audience is. Does he appeal to suburban women and swing voters or just to his base? Or does she feel it's women and minorities that she has to talk to or those blue-collar Democrats who are flocking to Trump?
SIEGEL: Mara, a lot of what's going on now is each side trying to frame the narrative around this debate. And how would you describe how each campaign has been trying to do that in recent days?
LIASSON: Both sides have been working the refs very hard. Clinton's campaign has been asking for fact-checking in real time. They want the moderator to call Trump out if he says something that's not true. They want the television networks to have the screen crawl point that out.
Trump's campaign has said the system is rigged against him. He said the moderators are in the tank for Clinton. He called Lester Holt a Democrat when in fact Lester Holt, who is an experienced journalist, is a registered Republican. So he's getting ready to have - to say, if he falls short in the debate, it's the moderators fault, the media's fault.
SIEGEL: There's always some question as to how important the debate is. These are not new faces whom we're seeing in this debate tonight. How important do you think it'll be?
LIASSON: That's a good question. I think this will be important. Possibly as many as a hundred million people could be watching. There's not that many undecided voters, but this is a very close race. So it is potentially important. And it won't be judged in its totality.
It's going to be judged by moments and those moments, we've known in the past - where's the beef? There you go again. You're no Jack Kennedy. Those moments get chewed over relentlessly after the debate on cable news, and a group verdict gets formed about who won and who lost. So working the refs isn't...
LIASSON: ...Just about what happens at the debate. It's trying to shape the narrative afterwards.
SIEGEL: NPR's Mara Liasson, thanks. Transcript provided by NPR, Copyright NPR.