President-elect Donald J. Trump has revived talk of abolishing birthright citizenship — the guarantee, rooted in common law and enshrined in the Constitution for more than 150 years, that anyone born in the United States is automatically an American citizen.

“We’re going to have to get it changed,” Mr. Trump said in a televised interview on Sunday. “We’ll maybe have to go back to the people. But we have to end it.”

Mr. Trump was vague in the interview about how he intended to proceed once he takes office. He raised the issue during his first term in office but did not take significant action then.

Here is what you need to know about birthright citizenship and whether the president could put an end to it.

Does the Constitution guarantee birthright citizenship?

Yes. The 14th Amendment says, “All persons born or naturalized in the United States, and subject to the jurisdiction thereof, are citizens of the United States and of the State wherein they reside.”

The part about jurisdiction creates a very narrow exception that today essentially applies only to children of accredited foreign diplomats. Other than that, the citizenship or immigration status of a person’s parents has not been held to have any effect on this right.