US President Donald Trump criticised birthright citizenship minutes after Supreme Court arguments concluded in a key case examining his administration’s restrictions on the policy.

In a post on Truth Social, his first public reaction after the hearing, Trump wrote, “We are the only Country in the World STUPID enough to allow ‘Birthright’ Citizenship!”. The arguments lasted about two hours, with the justices expected to deliver a ruling by the end of the court’s term in June.

Justices question legality of Trump’s order

During the hearing, both conservative and liberal members of the Supreme Court of the United States raised concerns over whether Trump’s executive order aligns with the Constitution and existing federal law.

The order seeks to deny automatic citizenship to children born in the United States to parents who are either in the country illegally or temporarily. It is part of a immigration crackdown pursued by the Trump administration.

Several justices pressed the government on the legal foundation of the move and also questioning how it would work in practice.

“Is this happening in the delivery room?” Justice Ketanji Brown Jackson asked the logistical challenges of determining citizenship at birth.

Justice Clarence Thomas appeared more open to the administration’s position, asking, “How much of the debates around the 14th Amendment had anything to do with immigration?”

Trump makes rare appearance in courtroom

Trump attended the proceedings, becoming the first sitting US president to be present during Supreme Court arguments. He stayed for just over an hour, listening as Solicitor General D. John Sauer defended the administration’s position.

He left shortly after lawyer Cecillia Wang began arguing in favour of maintaining broad birthright citizenship protections.

Throughout the session, Sauer faced sustained questioning from the bench, with justices probing both the constitutional interpretation and the real-world implications of the policy.

A challenge to long-standing precedent

The important aspect of the case is whether Trump can reinterpret the Citizenship Clause of the 14th Amendment, which has long been understood to grant citizenship to nearly everyone born on US soil.

The amendment states that “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.”

Lower courts have consistently blocked the executive order, finding it likely violates both the Constitution and federal law. They have also relied on the Supreme Court’s 1898 ruling in United States v. Wong Kim Ark, which affirmed citizenship for a US-born child of foreign nationals.

Administration defends narrower interpretation

The Trump administration argues that the prevailing interpretation is incorrect. It contends that children of noncitizens are not fully “subject to the jurisdiction” of the United States and therefore should not automatically receive citizenship.

In court filings, Sauer urged the justices to correct what he called as a long-standing misunderstanding of the Constitution.

Opposing lawyers rejected that view. “We have the president of the United States trying to radically reinterpret the definition of American citizenship,” Wang said during arguments.

Potential impact and context

If implemented, the order could affect more than 250,000 babies born in the United States each year, including children of undocumented immigrants as well as those born to individuals legally in the country, such as students and green card applicants.

The case is the first major immigration policy from Trump’s current term to reach the Supreme Court for a final decision. It also tests the limits of presidential power in reshaping established legal interpretations.