AUDIE CORNISH, HOST:

The political fallout from that DNC email leak spilled out onto the floor of the Wells Fargo Center here in Philadelphia on this opening day at the Democratic National Convention. NPR's Scott Horsley is sitting next to me now and what - it's euphemistically the bird's eye view basically from where we are. You know, DNC chair Debbie Wasserman Schultz has already announced that she is resigning from her position. But, Scott, it seems like that hasn't really been enough, right?

SCOTT HORSLEY, BYLINE: Not enough to quiet the supporters of Bernie Sanders, who are vocally frustrated today. Not only did Debbie Wasserman Schultz give up her chairmanship of the DNC, she also gave up her gavel. She was supposed to gavel this convention to order this afternoon, but she was worried enough about a backlash that she opted to hand off the gavel to Stephanie Rawlings-Blake, the outgoing mayor of Baltimore.

That gesture did not satisfy the Sanders supporters though, and since they couldn't boo Debbie Wasserman Schultz here in the arena, they proceeded to boo just about every other speaker who mentioned Hillary Clinton by name, including the pastor who delivered the invocation.

Now, today the DNC issued a formal apology for the sentiments revealed in those emails. It said it doesn't reflect the party's commitment to neutrality, and that it's taking appropriate action to ensure this never happens again.

CORNISH: Right, the early part of the convention is supposed to be literally like welcome. Here are the rules and here's what we stand for and that's where we heard all the boos.

HORSLEY: And a lot of booing, a lot of chanting. It's been sometimes hard to even hear the speakers so far this evening. Now, it's not unusual to hear protests, you know, outside the arena. You and I passed through a gauntlet of protesters as we were making our way into the convention this evening. But it is striking to hear it inside the convention itself.

Now over the last hour I should say, it has been a bit tamer here in the Wells Fargo Arena. And just a moment ago, Clinton's campaign chairman John Podesta was introduced. I thought there might be some boos, but he was politely received. It's not entirely clear to me whether the Sanders supporters have kind of made their position known and now gotten it out their system, or if they're just saving their breath for prime time.

CORNISH: Right, and one of the voices we're going to hear in prime time - Senator Bernie Sanders himself. And it's actually not the first time he came out to speak today.

HORSLEY: No, we got sort of a preview of his prime time television address this afternoon when he spoke to supporters. He told them the revolution that he started is not over. He crowed about some of the changes that he's won in the Democratic Party platform and in the nominating process going forward. But he also reiterated his support for Hillary Clinton and his strong opposition to Donald Trump.

Now, Bernie Sanders himself was booed when he made that case for Clinton earlier today. But he said brothers and sisters, that's the real world we're living in. Later today, Sanders sent a text message to his delegates saying, I ask you as a personal courtesy not to engage in any kind of protest on the floor.

CORNISH: That's probably not how he expected to use that database of contacts, right.

HORSLEY: No, and in addition the Clinton and Sanders campaign teams are working on the floor tonight to try to preserve order. They're working together. We'll be watching to see if that joint effort works.

CORNISH: And there are other speakers tonight that are a nod to the Sanders supporters, one of which is Senator Elizabeth Warren.

HORSLEY: Yeah, giving the spotlight slot in - on this opening evening to Elizabeth Warren was sort of an olive branch to the progressive wing of the party. She's an icon to Democratic liberals. Like Sanders, Warren has endorsed Hillary Clinton. She's campaigned with Hillary Clinton. She'll be trying hard tonight to bring the progressives into the Clinton camp. We're also going to hear tonight from First Lady Michelle Obama. So that's kind of the prime time line up.

CORNISH: And finally the RNC. Looking back, did they get a bounce from their convention?

HORSLEY: There are some polls that show that the Republican ticket got a convention bounce. That could be just noise though. A lot of pollsters say wait till all the dust settles in a couple of weeks.

CORNISH: That's NPR's Scott Horsley. Scott, thank you.

HORSLEY: My pleasure, Audie. Transcript provided by NPR, Copyright NPR.