The United States Supreme Court has expressed significant doubt regarding former President Donald Trump’s executive order to restrict birthright citizenship, following oral arguments heard by the justices with Trump himself in attendance. This consequential case, which marked the first time a sitting president has attended arguments at the nation’s highest court, saw both conservative and liberal justices questioning the legality and practicality of the order. Trump's order declared that children born in the U.S. to parents who are in the country illegally or temporarily are not American citizens, a stance that has been consistently struck down by lower courts and has not taken effect anywhere in the country.

During Wednesday’s hearing, justices posed skeptical questions to Solicitor General D. John Sauer, who argued on behalf of the Trump administration. Justice Ketanji Brown Jackson, from the liberal bloc, pressed on the logistical challenges, asking, “Is this happening in the delivery room?” She also questioned how parents could prove their intent for permanent residency or dispute determinations of not having domicile. Justice Clarence Thomas, however, appeared most inclined to side with Trump, inquiring about the 14th Amendment’s historical context and its focus on granting citizenship to Black people, including freed slaves, rather than immigration.

The Trump administration's core argument is that the long-standing view of citizenship, based on the 14th Amendment and federal law since 1940, is incorrect. They assert that children of noncitizens are not “subject to the jurisdiction” of the United States and therefore are not entitled to citizenship. Sauer introduced the concept of “domicile,” arguing that those unlawfully or temporarily present lack the necessary domicile or allegiance to the U.S. He claimed that “unrestricted birthright citizenship contradicts the practice of the overwhelming majority of modern nations” and acts as a “powerful pull factor for illegal immigration” and has “spawned a sprawling industry of birth tourism.”

However, the justices repeatedly challenged these points, inquiring into the concept of “domicile” which is not explicitly in the 14th Amendment, and differing phrasings of citizenship in various U.S. laws. Chief Justice John Roberts referred to part of the government’s argument as “very quirky,” while Justice Elena Kagan noted the administration was using “pretty obscure sources.” Roberts also questioned the relevance of “birth tourism” claims to the legal analysis, to which Sauer responded that it showed the interpretation of the citizenship clause has been a “mess” in a “new world” of migration compared to the 19th century. Roberts retorted, “Well, it’s a new world, but it’s the same constitution.”

Representing the American Civil Liberties Union (ACLU), legal director Cecillia Wang defended broad birthright citizenship, arguing that Americans’ understanding has always been that everyone born on U.S. soil is a citizen, with narrow exceptions for children of foreign diplomats. Wang warned that reinstating Trump’s executive order would immediately strip thousands of babies of their citizenship and, under the government’s theory, could call into question the citizenship of “millions of Americans past, present and future.” She emphasized that “the 14th amendment’s fixed bright line rule has contributed to the growth and thriving of our nation” and cautioned against allowing current administration policy considerations to reinterpret the amendment’s original meaning.

The 14th Amendment, ratified in 1868 post-Civil War, 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.” This clause was intended to secure citizenship for Black Americans, including former slaves. The Trump administration’s interpretation, however, seeks to override over 125 years of legal precedent, including the 1898 Wong Kim Ark ruling, which affirmed U.S. citizenship for a child born to Chinese nationals with permanent domicile in the U.S.

If upheld, Trump’s executive order, signed on his first day in his second term, would dramatically impact the U.S. population. Research from the Migration Policy Institute projects that approximately 255,000 babies born annually would be affected, potentially increasing the unauthorized immigrant population by 2.7 million by 2045 and 5.4 million by 2075. The order would apply not only to children of undocumented immigrants but also to those with legal, but temporary, status, such as students and green card applicants. Specific plaintiffs in the case include individuals from Honduras, Taiwan, and Brazil, whose children would be denied citizenship under the order.

This case represents another significant test of Trump’s assertions of executive power against long-standing precedent. A definitive ruling from the Supreme Court is expected by early summer. Trump, who has previously reacted furiously to unfavorable court decisions, issued a broadside against the court on his Truth Social platform prior to the arguments, stating, “Dumb Judges and Justices will not a great Country make!” If the court rules against his order, it would mark a major setback for one of his signature policy changes, following the court’s previous striking down of his tariffs.