Principle and Policy in the Birthright Citizenship Case

If you had asked me a year and a half ago what the prospects were for President Trump's executive order limiting birthright citizenship if and when the issue made it to the Supreme Court, I would have said the Court would reject the order either 9-0 or 8-1, with 7-2 being my upper limit on dissents. The two dissenters I would have predicted, obviously, would have been Justices Thomas and Alito.

Professor Buchanan, who is, depending on one's view, either more cynical or less naive than I am about the Supreme Court, thought that the Court would likely uphold the order--even though, as he made very very clear in his February 2025 blog post, he believed the argument for doing so extraordinarily weak. But he noted how, with support from motivated legal scholars, off-the-wall ideas can become on the wall (in Professor Jack Balkin's memorable phrasing).

I never quite got all the way to Professor Buchanan's view, but my prediction grew closer to his a year ago, after the Supreme Court's decision in Trump v. CASA. There, the Court placed limits on the ability of federal courts to issue universal (or "nationwide") injunctions in a case whose merits involved a challenge to the birthright citizenship order. But despite being called out by Justice Sotomayor in dissent for failing to address the merits at all, the majority . . . well . . . failed to address the merits at all. That suggested to me that one or more Justices in the CASA majority thought the lawfulness of the Trump order was at least a difficult question. My suspicions were confirmed by the oral argument in Trump v. Barbara, which made very clear that two Justices was the floor, not the ceiling, for votes to uphold the Trump order.

Thus, I was discouraged but not especially surprised by the lineup in yesterday's ruling in the case. Taking a glass-half-full perspective, I'll call the outcome 6-3, even though one of the six, Justice Kavanaugh, voted to invalidate the order on only statutory grounds. He made very clear that, in his view, Congress could, in the future, strip citizenship from children born in the U.S. to parents who lack citizenship and are not here permanently. But because Congress has for decades been unable or unwilling to enact major immigration legislation (a point to which I'll return below), even if the Kavanaugh position had prevailed and the Court as a whole accepted the plaintiffs' statutory argument but rejected their constitutional one, the risk of Congress enacting Trump's policy as a statute would have been low.

While I wasn't especially surprised by the outcome or the too-close margin, I was very pleasantly surprised by the tone of the majority opinion of Chief Justice Roberts. He could have written an opinion of the sort that the Court occasionally writes, that went something like this: Yeah, we know that birthright citizenship with only the narrow exceptions recognized in Wong Kim Ark is kinda dumb. It incentivizes birth tourism and illegal immigration. But we're stuck with it unless there's a constitutional amendment. He didn't write that kind of opinion.

On the contrary, Roberts treated birthright citizenship as not merely dating to English common law but as a noble inheritance from the English common law. He treated antebellum state laws denying citizenship to Blacks as ugly not only because they were intertwined with the odious institution of slavery but because they departed from the common law rule of jus soli. He characterized the period in which uncertainty about the status of birthright citizenship arose in the last decades of the nineteenth century as infected by the anti-Chinese racism of the period. He pointedly rejected the dissents' characterization of birthright citizenship as a feudal relic: "Where the dissents see feudalism, the Framers of the Fourteenth Amendment saw emancipation." And Roberts concluded with a stirring rhetoric reminiscent of the (often unfairly maligned) writing style of Justice Kennedy:

Citizenship, then and now, was the right to have rights—to freely participate in our political community. The Framers of the Fourteenth Amendment extended that promise to “every free-born person in this land.” We keep that promise today.

Justice Thomas's interminable 91-page dissent is almost entirely devoted to buttressing the revisionist history that the Roberts majority rightly associates with ugliness of the past. Thomas doesn't engage in any serious way with the practical problems that would arise out of abandoning the simplicity of birthright citizenship for a test that turns on parents' domicile, which is both a complex factual question that needs to be decided on a case-by-case basis and one that, as Professor Hamburger explained at length on this blog in February 2025, our decentralized system of registering births is ill-equipped to handle. 

Here is the entirety of what Justice Thomas says in response to the practical difficulties of a domicile-based rule:

the Court suggests that “domicile” is a difficult concept to apply. But, “‘[d]omicile’ is, of course, a concept widely used in both federal and state courts for jurisdiction and conflict-of-laws purposes, and its meaning is generally uncontroverted." Mississippi Band of Choctaw Indians v. Holyfield, 490 U. S. 30, 48 (1989).

That is a non sequitur. The majority didn't say that the meaning of domicile is difficult to ascertain. It said that determining domicile in any particular case is complicated, turning on such notions as subjective intent to remain in a place. In Mississippi Band of Choctaw Indians, the question was what "domicile" meant in a federal statute. The Court explained the answer and applied it in a litigated custody case. The fact that courts know what domicile means certainly does not entail that it is simple to ascertain in any given case. It isn't. Justice Thomas's response to the majority is thus an own goal. It essentially concedes that any time a person is born in the U.S. to non-citizen parents, there would need to be litigation to determine where those parents are domiciled in order to ascertain whether the newborn is a citizen.

Justice Alito's dissent is equally unpersuasive in its attempt to deal with the implication that, under his view, children born to undocumented immigrants who know no other country would no longer be citizens. He says (on page 2 of his dissent) that "Congress can and should address their situation." But much later on he admits that this is highly unlikely, given the politics of immigration. He acknowledges (at page 31 of his dissent) that "Congress has not passed comprehensive immigration legislation" in forty years.

To be sure, the majority's response to Justice Alito's policy concerns about incentivizing birth tourism and illegal immigration are not very comprehensive, but they don't really need to be. For one thing, the U.S. faces a demographic decline that immigration, including most undocumented immigration, ameliorates. For another, the prospect of giving birth to a U.S.-citizen child from whom parents will risk being separated via deportation is not exactly the magnet for undocumented immigration that the dissenters, the Trump administration, and its allies believe. Moreover, as the majority observes, whatever incentives for birth tourism and illegal immigration exist as a result of birthright citizenship have existed for centuries. The majority ruling does not create any new problems.

Finally, Justice Alito says that other than Canada, the U.S. is "the only affluent nation where birth alone is

enough to establish citizenship." I'll have to take his word for that because although he supplied links (in footnote number 17), none of them works. It's notable, though, that there are a fair number of affluent nations that provide for conditional birthright citizenship (e.g., Australia, Germany, and UK) but, to my knowledge, none of them uses parents' domicile as a condition for the obvious reason that it is so highly contestable on the facts. True, had the Court ruled as the dissenters wished, Congress could, in theory, have legislated more readily determinate bright-line criteria for citizenship (so long as they were at least as generous as domicile in all cases), but, as I've emphasized and even Justice Alito acknowledged, that would have been highly unlikely to happen, given congressional gridlock on (fueled by rightwing nativist sentiment about) immigration.

-- Michael C. Dorf