Emily Schaefer supports mass deportations. She wants less immigration. And she opposes a path to citizenship for undocumented people who have been living in the United States for decades.

She is not a Republican.

Ms. Schaefer, 52, is a lifelong Democrat who said that she “cannot stand” Donald J. Trump. Yet she voted for him.

“I have never voted for a Republican, ever. But we are being flooded with immigrants who are prioritized over the needs of citizens,” said Ms. Shaefer, who lives in Beaverton, Ore.

Ms. Schaefer said that Mr. Trump’s tough approach to immigration resonated with her for many reasons. The quality of education at her 15-year-old son’s public school has declined because of the large population of students who do not speak English, she said. In Oregon, many undocumented people are eligible for health care, based on their low incomes. They receive assistance from nonprofits while needy Americans struggle, she said.

“It’s absurd what Biden and Harris have allowed,” she said.

The surge in migration across the southern border, which reached record levels during the Biden administration, has reverberated across the country and hardened many Americans’ views on immigration.

While Republican voters have shown the biggest shift, Democrats and independents have also moved to the right, according to polls conducted in recent months.