On Wednesday morning, the Supreme Court heard arguments in Trump v. Barbara, a case challenging President Donald Trump’s 2025 executive order banning birthright citizenship. Justices seemed skeptical of the administration’s argument, but by taking up birthright citizenship at all, they showed how much ground nativists have gained since Trump’s first term. The 14th Amendment is quite clear: “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.” Trump seeks to overturn this and create a new, effectively stateless American underclass, and he’s gotten alarmingly far.

Hours after being sworn back into office for his second term, Trump issued an executive order titled “Protecting the Meaning and Value of American Citizenship.” Under the order, children born to undocumented mothers — or to women in the country on non-immigrant visas — would no longer be citizens upon birth, unless the children’s fathers were citizens or permanent residents. The order’s provisions would take effect 30 days after it was issued. It was immediately challenged in court and several federal injunctions prevented its implementation, meaning birthright citizenship remains the law of the land for now.

Trump’s efforts hinge on the meaning of a specific clause: “subject to the jurisdiction thereof.” The administration contends that noncitizens and those who don’t have permanent residency are not subject to the jurisdiction of the United States, since they’re actually loyal to a foreign power. This interpretation would reverse not only centuries of US law but also precedent set by English common law, leaving hundreds of thousands of children without status or stateless upon birth. Karen Tumlin, the director of the Justice Action Center, called the case a “canary in the coalmine for our democracy”: if Trump can end birthright citizenship with the stroke of a pen, then no constitutional protection is safe.

All but the most conservative justices seemed unconvinced. Their questions largely focused on two landmark decisions. One was Dred Scott v. Sandford, the 1857 case in which the court decided that enslaved people were not citizens — which the 14th Amendment was ratified partly to overturn. The other was United States v. Wong Kim Ark, an 1898 case in which the court ruled that, despite the Chinese Exclusion Act, the American-born children of Chinese nationals were indeed US citizens.

After Justice Clarence Thomas asked Sauer how the citizenship clause responds to Dred Scott, Sauer acknowledged that the 1857 decision “imposed one of the worst injustices in the history of this court.” But he argued that Congress specifically ratified the 14th Amendment to grant citizenship to “newly freed slaves and their children” who, according to Sauer, had “a relationship of domicile” to the United States and no “relationship to any foreign power.”

Nineteenth-century legislators, Sauer argued, couldn’t have foreseen the problem of birth tourism. “There are 500 — 500 — birth tourism companies in the People’s Republic of China whose business is to bring people here to give birth and return to that nation,” Sauer said. The current interpretation of birthright citizenship “could not possibly have been approved by the 19th century framers of this amendment,” he said. “We’re in a new world,” he continued, “where 8 billion people are one plane ride away from having a child who’s a US citizen.”

Justice Neil Gorsuch, who was questioning Sauer, appeared unswayed. “It’s a new world,” he agreed, but “it’s the same Constitution.”

Chief Justice John Roberts called Sauer’s examples of existing exceptions — including children of ambassadors or enemies during a hostile invasion — “very quirky” and not necessarily comparable to“a whole class of illegal aliens who are here in the country.” Justice Elena Kagan noted that most of Sauer’s brief focused on people who are temporarily in the country on visas — but Trump’s executive order was clearly intended to restrict immigration, and the president has said so himself.

In 2019, Trump called birthright citizenship a “magnet for illegal immigration.” Last year, presidential adviser Stephen Miller said the US-born children of immigrants are just as much of a problem as the immigrants themselves. “With a lot of these immigrant groups, not only is the first generation unsuccessful,” Miller said in a Fox News interview, citing the Somali-American community, which the administration would soon target in Minneapolis, as an example. “You see persistent issues in every subsequent generation. So you see consistent high rates of welfare use, consistent high rates of criminal activity, consistent failures to assimilate.”

The administration has sought to restrict legal immigration in all its forms: it implemented a steep fee for H-1B work visas, has signaled it may end a work program for international students, and enacted a travel ban on several countries that is even affecting World Cup players. The operation is barefacedly racist. The president famously complained about “all these people from shithole countries” who migrate and expressed his desire to have “more people from Norway.” Last year, he cut the refugee resettlement cap to just 7,500 and prioritized the resettlement of white South Africans. The Department of Homeland Security has linked the “homeland” to a decidedly white vision of Manifest Destiny that, like debates about birthright citizenship, harkens back to the nineteenth century.

Experts are broadly in agreement that most justices weren’t convinced by the administration’s argument, but it’s not clear exactly how the court will rule.

If the court did hand Trump an unexpected victory, a series of grim questions would immediately come into play — starting with when the change kicks in. The order was supposed to be implemented on February 19, 2025, thirty days after Trump signed the order, and would have gone into effect if not for a number of federal injunctions. “If the court sides with Trump, it will have to decide on a date on which to begin applying the president’s interpretation of the 14th amendment,” César Cuauhtémoc García Hernández, a professor of civil rights and civil liberties at the Ohio State University College of Law, told The Verge. “Anyone born on or after that date and described in Trump’s order would be treated as a migrant rather than a U.S. citizen.”

Sauer asked the court to apply Trump’s executive order “proactively” and not retroactively, and backdating the change to 2025 would pose a number of problems, calling the citizenship of millions of children into question.

The Trump administration is trying to narrow who counts as an American while simultaneously pushing for policies that prevent noncitizens from participating in public life. The administration has tried to prohibit states from offering in-state tuition to undocumented immigrants who live there, revoked accreditation for training centers that work with noncitizen truckers, and has broadly sought to turn America into a “papers, please” country.

Trump was in the audience during Wednesday’s arguments, making him the first sitting president to attend oral arguments before the Supreme Court. His presence may have intended to intimidate skeptical justices into taking his side. Norman Wong, a direct descendant of Wong Kim Ark, was also outside the courthouse, according to the New York Times. Wong and his family embody the stakes of this case, and he had a message for the justices: “They will be shamed for history if they get this wrong.”