MIAMI — On a recent Saturday morning in South Florida, 50-year-old Edgar Ospina stood in a long line of immigrants to take the first step to become an American.

Ospina has spent almost half his life in the U.S. after emigrating from his native Colombia, becoming eligible for citizenship in 1990. But with Donald Trump becoming a more likely presidential nominee by the day, Ospina decided to wait no more, rushing the paperwork required to become a citizen.

“Trump is dividing us as a country,” said Ospina, owner of a small flooring and kitchen remodeling company. “He’s so negative about immigrants. We’ve got to speak up.”

Nationwide, immigrants like Ospina are among tens of thousands applying for naturalization in a year when immigration has taken center stage in the presidential campaign, especially in the race for the Republican nomination.

Trump, the GOP front-runner, has pledged to deport the estimated 11 million people living in the U.S. illegally. He’s also vowed to bar Muslims from entering the country and threatened to cut off remittances that Mexican immigrants in the U.S. send back home. And he’s called for building a border wall — among other proposals to deal with unlawful immigration, saying the federal government has failed to protect the border from people and drugs illegally entering the country.