WASHINGTON, D.C. — The Supreme Court on Wednesday heard oral arguments in Trump v. Barbara, a case challenging the legality of Executive Order 14160, which would eliminate birthright citizenship for children born in the United States to parents who are in the country without legal authorization or on a temporary basis. President Donald Trump attended the oral arguments in person, becoming the first president to do so.

Trump issued Executive Order 14160 during the first hours of his first day back in office. The order rests on the administration's contention that the phrase "subject to the jurisdiction thereof" in the Fourteenth Amendment covers anyone not authorized to remain in the country permanently.

Solicitor General D. John Sauer presented the government's case for upholding the order. Sauer argued that birthright citizenship demeans the gift of American citizenship, encourages illegal immigration, and has led to a birth tourism industry by foreigners from potentially hostile nations. He cited estimates that 1.5 million babies have been born to birth tourists from China alone.

Justice Sonia Sotomayor pressed Sauer during the arguments, asking, "What do we do with those debates and the fact that the proponents of both acts said everyone who's born in the U.S. will be citizens?"

Cecillia Wang, legal director of the American Civil Liberties Union, argued against the order. "Ask any American what our citizenship rule is and they'll tell you everyone born here is a citizen alike. That rule was enshrined in the Fourteenth Amendment to put it out of the reach of any government official to destroy," Wang said.

The Fourteenth Amendment, adopted in 1868 following the Civil War, states in its first sentence: "All persons born or naturalized in the United States, and subject to the jurisdiction thereof, are citizens of the United States." The amendment was ratified in the aftermath of the Supreme Court's ruling in Dred Scott v. Sandford, which had denied citizenship to anyone of African descent. Congress separately granted citizenship to Native Americans in 1924.

The central precedent interpreting the amendment's Citizenship Clause is the 1898 Supreme Court decision in United States v. Wong Kim Ark. That case involved a man born in California to Chinese parents who were not citizens under the Chinese Exclusion Act. After visiting China, he was denied reentry to the United States on the grounds that he was not a citizen. The Supreme Court ruled in his favor, writing that "The Amendment, in clear words and in manifest intent, includes that children born within the territory of the United States, of all other persons, of whatever race or color, domiciled within the United States."

Demographers predict that eliminating birthright citizenship would affect 2.5 million children over a decade, creating a permanent underclass exposed to deportation and with curtailed access to education, jobs, and benefits.