There are major Supreme Court decisions every term. But Trump v. Barbara, according to Justice Samuel Alito, is “one of the most important decisions in the history of the Court.” It is certainly one of the most notable cases in recent years.
The 6-3 decision is a sweeping reaffirmation that the Fourteenth Amendment’s citizenship clause codifies the traditional common‑law principle of jus soli. Under that principle, birth on U.S. soil, combined with being subject to U.S. law at the time of birth, confers U.S. citizenship. Only the narrow exceptions long recognized at common law and in U.S. v. Wong Kim Ark apply, such as being the child of a diplomat.
Put simply, the Barbara decision reaffirms that virtually everyone born on U.S. soil and subject to U.S. law is a citizen at birth. The citizenship clause of the Fourteenth Amendment sets a constitutional line on citizenship that cannot be changed through executive order, statute, or agency reinterpretation.
Still, there’s a lot to unpack in the decision. Here’s what you need to know.
What Brought This Case to the Supreme Court?
The case arose after President Trump issued Executive Order No. 14160, “Protecting the Meaning and Value of American Citizenship.” Issued on January 20, 2025, the EO told federal agencies to stop treating babies born after February 19, 2025, whose parents lacked permanent legal status, as citizens.
Several families, including parents of children born on U.S. soil, filed a nationwide class action in New Hampshire. They argued that the EO violated both the Fourteenth Amendment and the federal citizenship statute in 8 U.S.C. § 1401(a).
A federal court in New Hampshire agreed and issued a preliminary injunction that blocked the EO from taking effect. The government appealed to the First Circuit Court of Appeals. But before the appeals court could decide the case, SCOTUS fast-tracked it by granting certiorari before judgment, a procedural move for particularly important cases.
On April 1, the Justices heard oral arguments in the case. The justices focused on the text, history, and precedent surrounding the Fourteenth Amendment, which is reflected in their subsequent opinions.
By Soil or By Blood?
The questions before the court were whether the Fourteenth Amendment’s text guarantees birthright citizenship to virtually everyone born on U.S. soil, including children of parents who are here unlawfully or only temporarily, and what it means to be “subject to the jurisdiction” of the United States. Does that phrase mean being under U.S. law and power, or does it impose extra conditions based on domicile, immigration status, or parental status?
At its most basic, the question is whether U.S. citizenship is granted by soil or by blood. The Fourteenth Amendment speaks directly to this question. It states:
“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 case revolves around the phrase “subject to the jurisdiction thereof.” According to the majority opinion, written by Chief Justice John Roberts, the phrase was well understood at the time of the Fourteenth Amendment's ratification in the mid-19th century.
Roberts and the majority interpret the phrase through an originalist framework, tracing it back to English common law, where children “born within the dominions” of the sovereign owed natural allegiance in return for protection at birth.
For example, colonists born in America before the Revolution were considered subject to the King of England's jurisdiction and therefore were his subjects, even if their parents were not English citizens.
According to the majority, this understanding continued after independence and “prevailed in each and all of the states,” with American legal authorities and the New York Chancery in Lynch v. Clarke confirming that children of aliens born here, including “temporary sojourners”, were citizens.
At the time of ratification, therefore, the majority felt the phrase clearly meant that the Fourteenth Amendment applied to anyone who could be considered as governed by the sovereign power of the United States wherever it has territorial authority. It did not, and still does not, require domicile, lawful status, or parental citizenship.
Dred Scott and Wong Kim Ark
The previous Supreme Court case to address the question of birthright citizenship was United States v. Wong Kim Ark (1898). However, before discussing Wong Kim Ark, the majority focuses on Dred Scott v. Sandford (1856), the infamous Supreme Court case that held Black people could not become U.S. Citizens and is still noted as a partial cause of the Civil War.
Roberts describes Dred Scott as a departure from common law at the time, and the Fourteenth Amendment as a direct repudiation of that decision, one that specifically restored soil-based citizenship and moved it beyond what any ordinary legislation, president, or judge could roll back.
This interpretation is reinforced in Wong Kim Ark, Roberts wrote. He emphasized that the Court in Wong read “subject to the jurisdiction thereof” in the same sense as both common law and previous Supreme Court cases such as Schooner Exchange v. McFaddon (1812).
In Schooner Exchange, Chief Justice John Marshall (of Marbury v. Madison fame) explained that the federal government has “absolute and exclusive jurisdiction” within its own territory. This rejected international‑law or domicile‑based theories and explicitly recognized that aliens who come here for “business or pleasure” are fully subject to U.S. jurisdiction.
Based on the plain text of the Fourteenth Amendment, the history and context of the Fourteenth Amendment’s passage, and precedent going back to the founding of the U.S., the majority concluded that almost all U.S.-born children are citizens of the United States under the U.S. Constitution.
The Concurrence and Dissents
One could argue the real vote was 5.5 to 3.5. This is because Justice Kavanaugh concurred with the majority in finding Trump’s EO unlawful. However, he wouldn’t have done so on constitutional grounds. In his view, the Fourteenth Amendment does allow Congress to carve out further limited exceptions to birthright citizenship, provided they are “relevantly similar” to the existing exceptions laid out in Wong Kim Ark.
Justices Thomas, Alito, and Gorsuch each dissented separately, although Gorsuch partially joined Thomas’ dissent. In Thomas’ view (laid out in a whopping 97-page opinion), the Fourteenth Amendment grants citizenship only to people “domiciled” in the U.S., meaning those residing there permanently. According to Thomas, the Fourteenth Amendment’s main purpose was securing equal citizenship for freed slaves. He argues that it does not broadly grant birthright citizenship to children of immigrants whose parents are not domiciled in the United States.
Justice Alito, meanwhile, wrote to note that the majority was “degrading” U.S. citizenship by viewing it in such a broad light, including “birth tourists” and children of parents not in the U.S. legally. Instead, he would have held that the Fourteenth Amendment only conveys citizenship when a person is “not subject to any foreign power.”
Finally, Justice Gorsuch wrote to express his concerns over the majority’s reliance on the “sprawling” decision in Wong Kim Ark, which he says modern courts should not rely on except for any narrow holdings. He also views birthright citizenship as a medieval rule that doesn’t translate well to modern immigration realities.
Justice Jackson also wrote a separate concurrence, although she agreed in full with the majority, to contest Justice Thomas’ race-limited view of the Fourteenth Amendment. In Jackson’s view, the Reconstruction Amendments serve as a reset for the nation rather than a limited, race‑specific fix.
What It All Means
The question of birthright citizenship is, for now, settled. The majority, in basing the decision on constitutional grounds, has issued a strong reaffirmation of birthright citizenship, grounded in an originalist reading of the citizenship clause. A different result would have raised hard questions about how far originalist methodology can be stretched.
For the rest of us, the bottom line is that it is soil, not blood, that defines American citizenship.
