In Trump v. Barbara, decided today, the Supreme Court held that the Fourteenth Amendment guarantees American citizenship to children born in the United States even when their parents are undocumented immigrants or are here only temporarily. The decision invalidated President Trump’s Executive Order 14160, which declared that such children were not “subject to the jurisdiction” of the United States and therefore were not citizens at birth.

Chief Justice John Roberts wrote for a five-justice majority. The Court began with the text of the Citizenship Clause: “All persons born or naturalized in the United States and subject to the jurisdiction thereof, are citizens of the United States.” The central question was the meaning of “subject to the jurisdiction.” The administration argued that a child lacked the required connection to the United States when the parents were unlawfully present or maintained a permanent home elsewhere. The Court rejected that interpretation. Jurisdiction, it said, means the government’s legal power over people within its territory. Undocumented immigrants and temporary visitors must obey American law and may be arrested, prosecuted, or sued here. They—and children born to them—are therefore subject to American jurisdiction.

Much of the opinion traces the rule to English common law. Under the doctrine of jus soli, or “right of the soil,” nearly every child born within the sovereign’s territory became a natural-born subject. Citizenship rested on a reciprocal relationship: the sovereign provided protection, and the person born under that protection owed allegiance. The rule applied even when a foreign mother’s presence was “momentary and uncertain,” and even when the parents could be expelled. The traditional exceptions were narrow: principally children of foreign diplomats, enemy forces occupying territory, and people born within territories controlled by another sovereign.

The American states inherited this rule after independence. In the majority’s account, birth on American soil generally made a person a citizen regardless of the parents’ nationality or intentions. The Court quoted an early American authority stating that “[t]he child of an alien, if born in the country, is as much a citizen as the natural-born child of a citizen.”

The majority then placed the Fourteenth Amendment in the shadow of Dred Scott v. Sandford. Dred Scott had rejected the common-law principle and held that people descended from enslaved Africans could not be national citizens. In the majority’s phrase, “blood, not soil, was made the rule.” The decision provoked intense condemnation. Frederick Douglass insisted, “By birth, we are American citizens,” while Abraham Lincoln called Dred Scott an “astonisher in legal history.”

The Civil War and Reconstruction reversed that judgment. In 1862, Attorney General Edward Bates wrote that “every person born in the country is, at the moment of birth, prima facie a citizen . . . without any reference to race or color.” Congress adopted the Civil Rights Act of 1866 and then placed the citizenship rule in the Constitution through the Fourteenth Amendment. The Amendment’s principal Senate sponsor described its language as “simply declaratory of . . . the law of the land already.” According to the Court, the purpose was not merely to protect formerly enslaved people but to settle the national rule of citizenship permanently and place it beyond ordinary political change.

The majority also relied heavily on United States v. Wong Kim Ark, the 1898 decision recognizing the citizenship of a San Francisco-born man whose Chinese parents were not eligible for naturalization. Wong Kim Ark described the Fourteenth Amendment as “declaratory” of the “fundamental rule of citizenship by birth.” The present Court said that precedent covered children of permanent residents, temporary visitors, and undocumented immigrants alike. Foreigners who enter for “business or pleasure” receive no exemption from American law.

The administration and the dissents argued that citizenship should depend on the parents’ permanent allegiance or domicile. The majority found little historical support for that theory. Domicile and citizenship, it explained, are different: a person may live permanently in a country without becoming its citizen and may remain a citizen of a country while living elsewhere. A domicile test would also replace a clear rule based on birthplace with difficult inquiries into each parent’s legal status and intentions.

Finally, the Court emphasized what the constitutional text does not say. The words central to the Executive Order—“mother,” “father,” “lawful,” and “temporary”—are “absent from the Clause. For a simple reason: they did not matter.” A child born on American soil and governed by American law is a citizen at birth. Only the historically recognized, exceedingly narrow exceptions remain.