This essay first appeared on July 3, 2026 at Law & Liberty.
The Supreme Court’s decision in Trump v. Barbara extended birthright citizenship to almost any person born in the United States—including the children of undocumented immigrants and of mothers who enter the country for the sole purpose of giving birth here. In so ruling, the court made some serious legal and historical mistakes.
But miscalculations by the Trump administration contributed to the result. Had the president’s birthright citizenship executive order been somewhat narrower and defended correctly, the president might have accomplished more of his goals.
Trump v. Barbara did not address the validity or existence of birthright citizenship, as some media outlets have suggested. It discussed only the scope of birthright citizenship. Those of us born in the US of American or lawful resident alien parents would be birthright citizens under any conceivable decision in the case. The Trump administration argued that for a child to be a birthright citizen, that child must be born within the country of a domiciliary mother. The court decided that, with minor exceptions, only birth within the country was required.
Background
The Citizenship Clause of the Fourteenth Amendment grants citizenship to those “born … in the United States, and subject to the jurisdiction thereof.” The question before the court was the meaning of “subject to the jurisdiction.”
In an earlier article for Law & Liberty, I acknowledged that the issue is a difficult one, without any unimpeachable answers. One reason is the generally unacknowledged fact that the Fourteenth Amendment is poorly drafted. Another is the more widely acknowledged fact that the record of the Fourteenth Amendment’s proposal and ratification is unenlightening. Sponsors and opponents said varying things, sponsors differed from each other, and some speakers contradicted themselves. All we can be sure of is that the word “jurisdiction” cannot mean what it usually means or what it means elsewhere in the Constitution—that is, “within specified political boundaries.” This is because that interpretation would render the phrase “subject to the jurisdiction thereof” redundant.
I concluded that “there can be no perfect interpretation of the Citizenship Clause. But there is a best one: A child is born ‘subject to the jurisdiction’ of the United States when his or her parents are in allegiance to the United States.”
I reached that conclusion for several reasons. First, some of the Fourteenth Amendment’s congressional advocates defined “subject to the jurisdiction thereof” with reference to allegiance, and no one contradicted them. Second, several illustrations they gave of persons not “subject to the jurisdiction”—the children of foreign diplomats and tribal Indians—meshed well with traditional exceptions to allegiance. Third, during the nineteenth century, the Supreme Court itself said that “subject to the jurisdiction” was tied to the concept of allegiance.
These facts rendered it fairly predictable that the court would adopt an allegiance theory rather than the Trump administration’s weaker “domicile” theory.
Unfortunately, however, the version of allegiance the court adopted was wrong.
Allegiance
During the Founding era and subsequently, under Anglo-American law and international law, a sovereign owed a duty to protect the people, and the people owed a reciprocal duty to obey the laws of the sovereign. Despite a suggestion to the contrary in Justice Alito’s dissent, it made no difference whether those bound by the duty were called subjects (as in a monarchy), members (as in Article IX of the Articles of Confederation), or citizens, as in the Constitution and in most republics. Whatever the inhabitants’ designation, their duty to obey was called allegiance.
Two of the dissenting opinions dismissed allegiance as a “feudal” or “medieval” concept. But this is true only in the sense that the “fee simple” is a feudal or medieval concept. Both arose in a feudal context, but in somewhat altered form have remained important into the modern era. The doctrine of allegiance certainly prevailed when both the Constitution and the Fourteenth Amendment were adopted.
But if the dissents undervalued allegiance, the majority opinion mischaracterized it.
The majority indicated that, with very few exceptions, the sole requirement for allegiance was birth within a sovereign’s territory. This is incorrect. As Edward Coke wrote in his report in Calvin’s Case (1608) (the leading case on the subject), allegiance “is a quality of the mind, and not confined within any place.”
Admittedly, Coke overstated the matter somewhat. But his comment reflected an underlying truth. The tie of allegiance is fundamentally a contractual or quasi-contractual one, not a territorial one. The subject (or citizen) agrees to obey in exchange for the sovereign’s protection.
In the case of a naturalized subject or citizen, the agreement is express. It is also express in the case of a person living in a host nation and whose own country is at war with the host, but who obtains special permission from the host nation to remain there.
But as in the case of John Locke’s social compact, allegiance is more often implied. It is implied when a person is born within a country to parents legally present there and the person chooses to remain there. It is implied when a foreigner, such as a tourist, enters a country legally: The foreigner is said to be in “local allegiance” to the host country, even while remaining in a superior allegiance to his homeland.
But—and this is a key point the majority underplayed—a person also may be within a country in circumstances where no promise to obey the laws can be inferred. The framers of the Fourteenth Amendment recognized two instances: foreign diplomats and Indians then living in American territories, but owing obedience only to their tribes. Another instance is a person living in a host country whose native land is at war with the host (unless the person receives permission to stay).
But no allegiance can be inferred from an invader or, for similar reasons, from one who entered or stayed in a country in deliberate defiance of her laws.
The Court’s Mischaracterization of Allegiance
The court’s opinion recognizes that allegiance has roots in the English common law (as well as international law). But the court’s version of allegiance grants an undeserved primacy to mere place of birth.
Thus, the opinion seeks to demonstrate that prior to the Fourteenth Amendment, the children of illegal aliens born in this country were recognized as citizens. However, its supporting evidence is exceedingly thin, consisting only of two references. One is the public “outcry” during the nineteenth century resulting from the attempted expulsion of an Irish pauper from the United States. This incident, though, is irrelevant because the pauper could not have entered the country illegally: There were no federal immigration restrictions at the time.
The other supporting reference is stated in this way:
“A foreign mother could enter the British Isles, give birth, and leave with her child the very next day, and that child would remain a British subject. [No citation given] … The same rule applied to children born in the realm of parents subject to expulsion. For example, children of “gypsies” (today, called Romani or Roma people) born in the realm were natural-born subjects, notwithstanding that British law at the time “directed” the Roma people “to avoid the realm” under “pain of imprisonment” or even death. 4 Blackstone 166 (1769); see Brief for Gerard N. Magliocca as Amicus Curiae 2–4.”
This claim that Roma children born in Britain were treated as natural-born subjects is based on a faulty reading of Blackstone and of a parliamentary statute adopted in 1553, during the reign of Queen Elizabeth (5 Eliz. i, c. 20).
During the prior reign of Queen Mary, Parliament had enacted a law addressing criminal and antisocial conduct by Roma people, who were members of a distinct ethnic group calling themselves “Egyptians.” The measure provided for various penalties, including expulsion from the kingdom. It also featured incidental provisions against native-born Englishmen who joined the “Egyptians” in their disreputable activities.
The 1553 statute, however, addressed not the Roma, but only their English fellow-travelers. The law described them as “Vagabonds, calling themselves Egyptians.” The last section of the statute provided that those born within the kingdom could not be expelled. Read in isolation, the last section might seem to apply to Roma children, but read in context with the rest of the statute, it appears to refer only to the English “vagabonds” who pretended to be Roma.
In fact, even if one did read the final section to include Roma children, it seems more of an act of grace than a definition of allegiance.
The Administration’s Mistake
The Trump administration’s domiciliary theory was unpersuasive. It did not have the historical and judicial foundation that allegiance did. Moreover, it is not accurate. For example, in defense of the theory, Justice Thomas wrote, “Once a person became domiciled in a place, he was considered no longer subject to any foreign power.” But of course this is not true: A sovereign certainly can conscript its citizen ex-pats for military service, and perhaps affect them in other ways.
Moreover, as acknowledged by both Justice Thomas and Justice Gorsuch in their dissents, adoption of the domicile theory would trigger additional vexing questions: May an illegal entrant ever acquire domicile? (By the normal understanding of the term, it would seem that he can.) If so, when?
This difficulty may explain why the dissenters focused more on birth tourism than illegal immigrants. In defending the case, the Trump administration similarly focused on birth tourism. The president’s reaction to the court’s decision showed the same emphasis, and so has the reaction of conservative media. Yet the status of the children of illegal migrants residing in the United States would seem to be the more important issue by far.
The irony is that if the Trump administration had persuaded the court to adopt an accurate allegiance theory, it would have won most of what it wanted. The children of illegal aliens would not be citizens. The children of “birth tourists” also would not be citizens because, due to a 2020 Biden-era regulation, entering the country for birth purposes is illegal.
The administration’s only concession would be that legitimate foreign sojourners are in “local allegiance” to this country, so if they happen to have children while they are here, those children would be birthright citizens. This hardly seems to be a serious problem.
