Four words are at the center of one of the biggest Supreme Court cases in decades: “subject to the jurisdiction thereof.”

The full text of the 14th Amendment’s Citizenship Clause reads: “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.”

Everyone agrees on what “born in the United States” means. The entire fight is over those four words — “subject to the jurisdiction thereof” — and what they were intended to exclude.

What the Amendment Was Written to Do

The 14th Amendment was ratified in 1868, directly after the Civil War, as a constitutional response to the Supreme Court’s Dred Scott decision. That ruling had held that Black Americans could never be citizens regardless of where they were born or whether they were free. The amendment’s framers wanted to make citizenship a constitutional guarantee that could never be stripped away by legislation or judicial interpretation.

The citizenship clause was designed to be broad and durable. Its authors — including Senator Jacob Howard of Michigan, who introduced the language — explicitly stated it would cover all persons born in the United States except for two categories: children of foreign diplomats, and members of Native American tribes who maintained a separate political allegiance to their tribal governments.

That was the original scope of the “subject to the jurisdiction” exclusion. Children of aliens residing in the United States — even those without formal legal status — were considered subject to American jurisdiction and thus entitled to citizenship at birth.

The Administration’s Argument

The Trump administration reads the history differently. Its legal team argues that “subject to the jurisdiction” requires a complete and permanent allegiance to the United States — the kind of allegiance that citizens and legal permanent residents owe, but that illegal immigrants and temporary visa holders do not.

Under this reading, a foreign national who entered the country illegally owes primary allegiance to their home country, not to the United States. Their presence here is a violation of American law, not a basis for acquiring American benefits. The phrase “subject to the jurisdiction” was meant to include only those who have fully submitted themselves to American legal authority — not those who are in the country in violation of it.

The administration also cites the 1884 case Elk v. Wilkins, in which the Supreme Court ruled that Native Americans born within the United States were not automatically citizens because their primary allegiance was to their tribe, not the federal government. The argument is that the same logic applies to children of those whose primary legal allegiance lies elsewhere.

The Landmark Precedent

The strongest obstacle to the administration’s position is the 1898 case United States v. Wong Kim Ark. In that decision, the Supreme Court ruled 6-2 that Wong Kim Ark — born in San Francisco to Chinese immigrant parents who were not American citizens — was an American citizen at birth by virtue of the 14th Amendment.

The majority opinion, written by Justice Horace Gray, grounded birthright citizenship in centuries of English common law tradition and held that the 14th Amendment codified the principle that birth on American soil confers citizenship, with only narrow exceptions.

The Trump administration argues that Wong Kim Ark was decided in an era before modern immigration law existed — before there was such a thing as “illegal” immigration — and that the ruling should not be read to extend citizenship to those whose presence in the country is itself unlawful.

The Originalist Tension

Here is where the debate gets genuinely complicated for conservatives who embrace originalism — the idea that the Constitution should be interpreted according to its original meaning.

The original meaning of the citizenship clause, based on the legislative history, appears to support broad birthright citizenship. Senator Howard’s floor statements, the debates surrounding ratification, and the Wong Kim Ark ruling together make a strong originalist case for the current interpretation.

The administration is essentially asking the court to adopt a different kind of originalism — one focused less on the intent of the amendment’s framers and more on the structural logic of citizenship as a concept rooted in allegiance.

This is not a frivolous argument. But it is a demanding one. And tomorrow, we will find out how the nine justices respond to it.