DAVID GREENE, HOST:
Donald Trump has energized millions of Republican voters with his tough talk on immigration.
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DONALD TRUMP: I will build a great, great wall on our southern border. And I will have Mexico pay for that wall.
GREENE: But that same language could have an unintentional side effect in a general election. Many immigrants are trying to become citizens before November so they can vote against Trump, as NPR's Asma Khalid reports.
ASMA KHALID, BYLINE: Jose Lovos has been living in the U.S. legally for 20 years. He moved from the war-torn country of El Salvador. And these days, he's a maintenance guy at a hotel. He lives in Virginia with his wife and three kids. And he tells me he could have become a citizen years ago, but he just never got around to filling out the paperwork.
JOSE LOVOS: I never before have interest to apply for citizen.
KHALID: We started speaking in English, but Lovos is more comfortable speaking in Spanish.
LOVOS: (Through interpreter) I wasn't very interested before in becoming a citizen because we weren't too worried about anything. But now there's all this rhetoric about deporting 11 million undocumented people.
KHALID: And on Christmas Day, he and his wife decided it was time to become citizens.
LOVOS: (Through interpreter) Because we want to help elect a good president for people in this country who don't have a voice or a vote. I want to become a citizen to help other people because other people have done it for me in the past - citizen to the people who have power to make change.
KHALID: Lovos tells me the main reason he's becoming a citizen now is so that he can vote in November against Trump.
LOVOS: (Through interpreter) I don't understand why he has to generalize. Candidates can't say all immigrants are bad or that we have to deport them all.
KHALID: There are about 9 million people like Lovos in the country - legal permanent residents who are eligible to become citizens. And in the months after Trump announced his bid for president, citizenship applications were up 15 percent compared to the year before. Applications tend to spike in election years. But this year, there's also been an intense push by immigrant groups because of Trump. Together, they've held more than 300 workshops across the country in recent months.
UNIDENTIFIED MAN: Why choose naturalization? (Speaking Spanish).
KHALID: I went to one in Miami, and I met Mauricio Lotero in the crowd. Lotero is from Colombia. And he says he came to this workshop because of Trump.
MAURICIO LOTERO: If Donald Trump is the president of the United States, maybe the immigrants or my citizenship will be affected in the future, you know?
KHALID: He says he wants to vote.
LOTERO: I don't want Donald Trump expressing. So that's one of the reasons that I want to vote because I want to vote against Donald Trump.
KHALID: It's hard to say for certain whether the spike in citizenship applications is a correlation or a causation. But David Damore with the public opinion research group Latino Decisions says he's seen this pattern before.
DAVID DAMORE: We found this in California - some work I did with Latino Decisions on the effect of Proposition 187 in the early 1990s.
KHALID: Prop 187 was a ballot initiative in California. It sought to eliminate government services, including K-12 schooling, for people living in the state illegally. The measure passed, but it was never implemented. Still, in the years following, Damore says Latinos were mobilized.
DAMORE: So you saw more participation, but you also saw more people who were eligible to naturalize naturalizing.
KHALID: And it's true. Stats from U.S. Citizenship and Immigration Services show there were record numbers of citizenship applications in 1996 and 1997.
DAMORE: It was that threat that has been proven to be an important mobilizer among immigrants to get them to naturalize and then eventually participate in the political process.
KHALID: We don't know for sure how many people are naturalizing this cycle because we don't have the final data yet. But people who become citizens tend to vote at a higher rate than people who are born citizens. Asma Khalid, NPR News. Transcript provided by NPR, Copyright NPR.