Ann E. Marimow

So to have him actually there in person face to face with the justices sent a real signal.

So you'll remember the president on his first day back in office issued this executive order to really limit the guarantee of birthright citizenship and say it does not include the children of illegal immigrants or the children of many temporary foreign visitors.

That was seen as an open challenge to the long-held understanding of the 14th Amendment, and there were lawsuits filed immediately by Democratic state attorney generals and expectant parents.

Yes.

And not just in the 14th Amendment, but in subsequent court rulings, in actions by past presidents, this has been the common, subtle law understanding.

President Trump's Solicitor General, John Sauer, who represents the administration at the Supreme Court, is asking the justices to reinterpret or restore what he says is the original meaning of the 14th Amendment.

So a key point to the administration's argument centered on the language of the 14th Amendment and the meaning of a phrase, subject to the jurisdiction of.

The language of the 14th Amendment says that all persons born or naturalized in the United States and subject to the jurisdiction thereof are citizens of the United States.

John Sauer is trying to get the justices to focus on, again, the meaning of subject to the jurisdiction of.

In his view, the babies of illegal immigrants are not subject to the jurisdiction of the United States and are therefore not citizens.

So the administration's argument really rests on one of the court's rulings in 1898, and this is the case of Wong Kim Ark.

There, the court ruled that a man born in San Francisco but to Chinese immigrants was a citizen.

And John Sauer says, we've been thinking about that case all wrong.

It's been read too broadly to apply to a larger group of people.

And really, he says the key in that decision is the word domicile and the fact that Mr. Wong's parents were legally present in the United States, even though they were not citizens.

They had a commitment to living in the U.S.

And for that reason, when their son was born in San Francisco, he was a citizen.

And so throughout the argument, John Sauer asked the justices to focus on that word and saying that that's key to someone being able to become a birthright citizen.

Absolutely.

It did come up a lot.