WATCH: ‘What do states do with a newborn?’ Kavanaugh quizzes Trump lawyer on birthright order

Supreme Court Justice Brett Kavanaugh asked the Trump administration Thursday to explain the practical details of ending birthright citizenship for people born in the United States to parents who entered the country illegally.

Listen to Kavanaugh’s remarks in the video player above.

“How is this going to work?” Kavanaugh asked U.S. Solicitor General D. John Sauer. “What do hospitals do with a newborn? What do states do with a newborn?”

“I don’t think they do anything different,” Sauer said. He noted that the executive order states that the federal government will not accept “documents issued by State, local, or other governments or authorities purporting to recognize United States citizenship” to people who are affected by the new policy. Kavanaugh repeatedly pushed Sauer to explain how federal officials would determine a newborn’s status.

LISTEN: Supreme Court hears arguments on Trump’s challenge to birthright citizenship

Thursday’s oral arguments in the consolidated case, Trump v. CASA, Inc., dealt with whether federal judges have the power to issue nationwide injunctions that block the administration’s actions.

The executive order, signed by the president shortly after he took office on Jan. 20, affects people in the following two situations: when their “mother was unlawfully present in the United States” and “father was not a United States citizen or lawful permanent resident at the time of said person’s birth,” or when their “mother’s presence in the United States was lawful but temporary” and their “father was not a United States citizen or lawful permanent resident at the time of said person’s birth.”