Updated April 1, 2026 at 1:48 PM CDT
A majority of Supreme Court justices peppered Solicitor General D. John Sauer with skeptical questions about the Trump administration's position that birthright citizenship should not apply to babies born to immigrants in the country illegally.
That included conservatives Chief Justice John Roberts and Justices Neil Gorsuch, Brett Kavanaugh and Amy Coney Barrett.
If conservatives were skeptical of Sauer, Justices Gorsuch and Barrett, in particular, had hard questions for Cecillia Wang, legal director of the American Civil Liberties Union who argued against Trump's position, too, and could be potential swing votes.
Roberts, at one point, called some of what's undergirding Sauer's arguments "quirky and idiosyncratic."
Gorsuch quizzed Sauer on immigration laws in 1868 when the 14th Amendment, which guarantees automatic citizenship to those born on U.S. soil and said some of the Sauer's sources for his argument were "like going back to Roman law."
When Sauer used a previous Supreme Court case, Wong Kim Ark, widely believed to be precedent upholding birthright citizenship for all born on U.S. soil, Gorsuch joked, "I'm not sure you want to apply Wong Kim Ark."
Kavanaugh pressed Sauer on language differences between the 14th Amendment, which was enacted in 1868, and the Civil Rights Act of 1866.
The 1866 law mentions that people would be citizens, who are "not subject to any foreign power."
The 14th Amendment does not use that phrase, instead stating: "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."
Sauer argued that the intent was the same with both laws.
"Why didn't they say the same thing?" Kavanaugh responded.
Kavanaugh also dismissed the idea that many other countries don't have birthright citizenship.
"I'm not seeing the relevance as a legal, interpretive matter," Kavanaugh said. Sauer agreed that it wasn't relevant legally.
Justice Barrett said part of Sauer's argument was "puzzling" — about why the framers didn't make citizenship explicitly tied to bloodline (jus sanguinis) instead of soil (jus soli) as other countries did.
The strongest questioning for Wang came from conservative Justice Samuel Alito. He asked several questions and sparred with Wang on the idea of the intent of the 14th Amendment. Wang acknowledged that the "intent" of both laws was the same, but noted that Wong Kim Ark's ruling points out that the 14th Amendment clears up that ambiguity.
Under questioning from Kavanaugh, Wang noted that the phrase "foreign powers" refers specifically to the exception that children of ambassadors do not qualify for automatic citizenship.
Outside the court, dozens of people rallied in support of birthright citizenship
Volunteers with the ACLU, joined by immigrant rights organizations like CASA and the League of United Latin American Citizens, handed out fliers that read "protect birthright citizenship" and "14th Amendment."
"We're all out here to protect the fundamental right of birthright citizenship. It's written in the 14th Amendment," said Anu Joshi, a staff member of the ACLU. "It's what makes us America."
Among the crowd were several people who were citizens by birthright themselves.
"I am a birthright citizen so this hits really, really close to home because without birthright citizenship I wouldn't even have my citizenship in the United States," said Stephanie Sanchez, a first-generation Mexican-American who came to the rally. "Here I am representing my community and fighting back."
After the arguments, ACLU Executive Director Anthony Romero told the crowd he felt confident in the way the arguments played out inside.
"We are fighting for the heart and soul of this country. The fight to protect birthright citizenship is about our neighbors, our families, our kids. It's not about the past, it's about the future," he said. "We will only accept what is just and what is right."
Largely absent from the crowd were proponents of the president's position, though Trump himself was at the Supreme Court today, making him the first sitting president to attend oral arguments at the nation's highest court. Trump left the court after Sauer concluded his arguments and did not stay for the entirety of the ACLU's arguments.
An opinion is expected this summer.
This story will be updated.
Ximena Bustillo and Anusha Mathur contributed to this story.
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