DAVID GREENE, HOST:
Cory Booker has confirmed this morning that he is suspending his presidential campaign. In a letter to his supporters, the New Jersey senator said he doesn't have the campaign funds to compete in what is still a crowded Democratic primary field.
Now, Booker's departures comes three weeks before the Iowa caucuses. One candidate having a good few days in that state is Bernie Sanders. The Vermont senator picked up an endorsement from an influential progressive group, and a well-regarded poll puts Sanders slightly ahead of his Democratic rivals in the state. This comes as Sanders' campaign has started going after other leading Democrats more forcefully.
NPR political reporter Juana Summers joins us now from the college town of Iowa City, Iowa. Hi, Juana.
JUANA SUMMERS, BYLINE: Hey, there.
GREENE: So how did Sanders spend his weekend?
SUMMERS: He had a really busy weekend here in Iowa. Perhaps the biggest event was this climate-focused town hall he held here in Iowa City. It drew a really young, diverse crowd. Sanders specifically called out the work of the Sunrise Movement. They are those young activists who have been putting pressure on Democrats for months to more forcefully address climate change. And they've really put the idea of the Green New Deal into the forefront of the Democratic race for the White House. And Sunrise came out over the weekend and said that their members were endorsing Bernie Sanders.
GREENE: Sanders is not the only Democratic candidate who has been speaking with a lot of urgency about climate change. Did the group give any sense for why they chose him over others?
SUMMERS: Yeah, they did. So I spent some time talking to these young activists, and they say that while other folks were talking about climate change, it's Bernie Sanders who most forcefully speaks out about the urgency of addressing what they see as a generational crisis. I sat down with Varshini Prakash, who is a co-founder of the group. And I asked her why she thought - that the activists so overwhelmingly back Sanders.
VARSHINI PRAKASH: He has been a vocal climate champion for his entire career. He said things like climate change was the greatest geopolitical threat facing America in 2016 and was laughed off for it. Now that's become a main position.
SUMMERS: It remains to be seen how much of this endorsement moves things for Sanders here in Iowa and elsewhere, but it certainly points to the fact that this is a candidate who continues to perform really strong with the youngest voters.
GREENE: Does the endorsement point to anything about Sanders' campaign this year, do you think?
SUMMERS: It does. One of the things we're really seeing, David, is that a lot of progressive groups are moving in Bernie Sanders' direction. He's got the energy among the Democrats' last flank. Yesterday in New Hampshire, he also got the endorsement of the SEIU, the labor union in New Hampshire. We've also seen him get backing from a number of notable progressives, including Representative Alexandria Ocasio-Cortez. And one of her congressional allies, Representative Rashida Tlaib of Michigan, was stumping for Sanders, too.
GREENE: Which seems to maybe be working for Sanders. I mean, last week, some new polling came out - I mean, we should say it shows a very close race among the top four candidates or so. But Sanders holds a narrow lead. I mean, how is that dynamic playing out on the ground?
SUMMERS: Yeah, that's right. This race is getting tighter. And as that's happening, Sanders is - his campaign are starting to go after other top-tier candidates more aggressively. Nina Turner, who is one of Sanders' campaign co-chairs, wrote an op-ed for one of the biggest newspapers in South Carolina, where she essentially argued that former Vice President Joe Biden has repeatedly betrayed black voters and undermined progress. Biden, of course, continues to perform very strong with black voters in polls. And separately, the Sanders campaign has accused Biden of rewriting history over his vote for the Iraq War, something that's come up obviously quite a lot with the recent conflict in the Middle East.
GREENE: Sanders has gone after Biden before, right?
SUMMERS: Yeah, although it's escalated some. But we're also seeing something new - the Sanders campaign, though not the candidate himself, going after Elizabeth Warren despite months and months where these folks really haven't criticized each other. This comes up after Politico reported this weekend that the Sanders campaign used a script that explicitly suggested Warren was appealing to highly educated voters, wouldn't explain the party's coalition. Now, Sanders got asked about this. He said he'd just read this voter script. He didn't take responsibility for it. He said he had never attacked Warren, calling her a good friend but said that no one was going to be attacking her.
GREENE: NPR's Juana Summers in Iowa City. Thanks, Juana.
SUMMERS: Thank you. Transcript provided by NPR, Copyright NPR.
