Donald Trump’s campaign against immigration is having an unexpected consequence: immigrants are applying to become citizens so they can vote against him.

DENVER — Donald J. Trump’s harsh campaign language against Mexican immigrants has helped him win a substantial delegate lead in the Republican primaries, but it is also mobilizing a different set of likely voters — six in the family of Hortensia Villegas alone.

A legal immigrant from Mexico, Ms. Villegas is a mother of two who has been living in the United States for nearly a decade but never felt compelled to become a citizen. But as Mr. Trump has surged toward the Republican nomination, Ms. Villegas — along with her sister, her parents and her husband’s parents — has joined a rush by many Latino immigrants to naturalize in time to vote in November.

“I want to vote so Donald Trump won’t win,” said Ms. Villegas, 32, one of several hundred legal residents, mostly Mexicans, who crowded one recent Saturday into a Denver union hall. Volunteers helped them fill out applications for citizenship, which this year are taking about five months for federal officials to approve. “He doesn’t like us,” she said.

Well, whaddaya know… Republicans aren’t the only party with a base.