On January 20, 2025, President Donald Trump issued an executive order purporting to limit birthright citizenship to children who have at least one parent who is a citizen or is lawfully admitted for permanent residence. Several immigrant rights nonprofits and individual immigrants challenged the order as a blatant violation of the Fourteenth Amendment, which states that “[a]ll 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.” According to the Trump administration, the children of noncitizen parents without lawful status, as well as the children of noncitizen parents whose status is “lawful but temporary,” are not “subject to the jurisdiction” of the United States and are not birthright citizens.

This is not the first time litigation around this executive order has reached the Supreme Court: in April 2025, CAC filed an amicus brief on behalf of an ideologically diverse group of scholars urging the Supreme Court to let lower court orders blocking the executive order take effect. In a disappointing decision, the Supreme Court limited the use of nationwide injunctions in blocking unconstitutional federal actions, but it did not decide whether the executive order was constitutional. After this decision, the United States District Court for the District of New Hampshire granted a preliminary injunction in a class action lawsuit, blocking the order. The Trump administration asked the Supreme Court to decide the case before the court of appeals had an opportunity to consider it, and the Court agreed. Now the merits of the executive order itself are before the Supreme Court.

In February 2026, CAC filed an amicus brief on behalf of an ideologically diverse group of leading scholars of constitutional law and immigration urging the Supreme Court to hold the order unconstitutional. Our brief makes three principal points.

First, the Fourteenth Amendment’s text guarantees birthright citizenship to children born to noncitizens, no matter their immigration status. The Citizenship Clause embodies the jus soli rule of citizenship under which citizenship is acquired by right of the soil rather than by bloodline. By extending citizenship to persons “subject to the jurisdiction” of the United States, the Clause sweeps broadly to include anyone who is “subject to the authority of the U.S. government.” Dictionaries and international legal practice at the time of the Fourteenth Amendment’s drafting and ratification confirm that virtually everyone born within the United States was considered to be subject to its jurisdiction. The only exceptions were exceedingly rare: foreign rulers, foreign diplomats, and foreign military forces, as well as members of American Indian tribes. Relatedly, common-law birthright citizenship did not attach to the children of foreign ambassadors, foreign ministers, and hostile occupying forces, as well as the children born into Indian tribes, who were viewed as members of distinct political communities.

Second, the history of the Citizenship Clause confirms that the Clause guarantees citizenship to children born in the United States, no matter what their parents’ immigration status is. The Framers were aware that the Clause would apply to the children of noncitizens—even those who were in the country unlawfully or who did not intend to stay in the country permanently. In the debates over the Civil Rights Act of 1866, which first affirmed the principle of birthright citizenship, opponents of the measure warned that it would apply to the children of non-citizen “Gypsies,” whom they described as “trespassers” in the United States. The Act’s advocates agreed that it would “undoubtedly” grant citizenship to those children. In the debates around the Citizenship Clause, as well, Members of Congress reiterated the simple, sweeping scope of birthright citizenship.

Finally, the Trump administration’s arguments about the text and history of the Clause are completely wrong. The administration claims that the Citizenship Clause uses “subject to the jurisdiction thereof” to refer not to regulatory jurisdiction or authority, but instead to “political jurisdiction” or “primary allegiance”—statuses that, they say, are only available to the children of parents who can establish a “lawful permanent domicil and residence here.” This is wrong, and the administration’s argument relies on cherry-picking, distortion, and disregard for the historical record.

The Fourteenth Amendment guarantees birthright citizenship to virtually all children born in the United States, no matter the immigration status of their parents. The Supreme Court should reject the Trump administration’s arguments and uphold the preliminary injunction.