Still, many of the new citizens at Mount Vernon on Tuesday remained optimistic about their place in the country. Mr. Esmaeili pointed to the vocal protests against Mr. Trump’s proposed travel ban earlier this year, explaining that he has found most Americans welcoming of outsiders.

“I believe in this system, and that’s why I’m here. I believe that one person — even if it’s the president — can’t do everything he wants. The people are important,” he said, looking forward to the next election in 2020.

“People are going to know that they made a mistake and they will re-elect someone more suited to America,” he added.

Others taking the oath on Tuesday were more hesitant. Muhammad Tai, 29, moved to the United States five years ago from Pakistan. As a Muslim, he said, the turn in public sentiment against outsiders has made life difficult in recent months. As a pharmacist, Mr. Tai is concerned about the health care legislation unveiled by Senate Republicans last month, which he said would leave his customers with unaffordable bills.

“I am in between,” he said. “I still love my country which I was born for, Pakistan, and I love the country of my future, America.”

As with the other new citizens from 44 countries, the naturalization ceremony was the end of a lengthy application process for Mr. Tai, including piles of forms, fingerprinting, a language test and an interview covering American history and culture.