AILSA CHANG, HOST:
President Trump is campaigning in Arizona tonight. The trip is part of a western swing to rally Republican voters ahead of the midterm elections, which are now just over two weeks away. Last night in Montana, he distilled the Republican closing argument heading into the midterm elections to this.
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PRESIDENT DONALD TRUMP: This will be...
TRUMP: ...An election of Kavanaugh, the caravan, law and order and common sense. That's what it's going to be.
CHANG: The caravan he's talking about is a group of migrants trying to reach the U.S. border. It's now a big feature in his stump speech. And joining us now to talk about all this is NPR White House correspondent Tamara Keith Hey, Tam.
TAMARA KEITH, BYLINE: Hi.
CHANG: So why is President Trump talking about another caravan at a political rally, you think?
KEITH: Well, this is not the first time he has talked about caravans. He talked about a different caravan back in April. This is a new one. And it's getting a lot of attention on cable news, and so he is talking about it again. He suggested at that rally - without offering any evidence, he made a claim that Democrats were somehow behind the caravan.
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TRUMP: But they wanted that caravan. And there are those who say that caravan didn't just happen. It didn't just happen. A lot of reasons that caravan, 4,000 people - but I just want to thank the Mexican government because they're stopping it, hopefully before it ever gets to Mexico.
KEITH: And we should underscore that there's really no evidence to back up this conspiracy theory that he's been able to offer. But you know, the reason that he is talking about this and talking about illegal immigration is that it's something that gets his supporters animated. You know, they are still at these rallies chanting build the wall almost every time he's out there.
CHANG: So basically, this is just an effort to rally the Republican base to get out and vote.
KEITH: Yeah. And the evidence is that it's a winning issue. There are two new polls from Pew that are out that find that illegal immigration is an incredibly salient issue among those who plan to vote Republican in the upcoming elections. They asked about 20 different issues facing the country. And those supporting Republicans in the midterms, 75 percent of them say that they consider illegal immigration to be a very big issue. Jocelyn Kiley is associate director of research at the Pew Research Center.
JOCELYN KILEY: You can see that there's energy among Republican voters around the issue of immigration. And that energy is most pronounced within the set of Republican voters who are really focused on border security and law enforcement.
KEITH: And so how do we know this is a base play? Illegal immigration in the way that President Trump talks about it is simply not a priority issue in the same way for Democrats or independent voters as it is for Republican voters. And for Republican voters, as she says, it can be a powerful motivator.
CHANG: I mean, wasn't this election supposed to be about the Republicans' tax cut, which was one of the president's biggest accomplishments? Why is he talking so much about immigration specifically now?
KEITH: Yeah. And immigration is an area where he hasn't accomplished as much as he would want to. Border crossings are apparently up. And you know, it's just - he hasn't gotten the wall, for instance. But it worked for him last time. He feels that this is an issue that works for him. He thinks talking about illegal immigration is one of the reasons that he's president of the United States now.
CHANG: That's NPR's Tamara Keith. Thanks, Tam.
KEITH: You're welcome. Transcript provided by NPR, Copyright NPR.