Donald Trump storms out of Supreme Court as he faces loss

Donald Trump has stormed out of the Supreme Court as one of his keystone policies came under the scrutiny of a sceptical bench.

Trump became the first president to attend a Supreme Court hearing in person to hear arguments on his birthright citizenship policy.

The president entered the courtroom without fanfare and was not acknowledged by the judges.

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After an hour sitting several rows back from the front of the public gallery, he got up and walked out.

He did not have another event on his schedule for 90 minutes after he left.

The president is looking to overturn a 1868 constitutional amendment, which automatically grants citizenship to anybody born on US soil.

But the judges did not appear to be impressed by his administration's case.

Solicitor-general John Sauer argued the citizenship clause of the 14th Amendment "was adopted just after the Civil War to grant citizenship to the newly freed slaves and their children".

"The clause thus does not extend citizenship to the children of temporary visa holders or illegal aliens," Sauer said.

"Unlike the newly freed slaves, those visitors lack direct and immediate allegiance to the United States."

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Even the conservative wing of the Supreme Court was sceptical of Sauer's argument.

"The examples you give to support that strike me as very quirky, children of ambassadors, children of enemies during a hostile invasion, children on warships," Chief Justice John Roberts said.

"Then you expand it to a whole class of illegal aliens are - are here in the country."

Sauer said there were eight billion people who were a plane ride away from having a child who is a US citizen.

"Well, it's a new world," Roberts said. "It's the same constitution."

Trump-appointed judge Neil Gorsuch pointed out that immigration laws were far stricter now than they were in 1868.

The president later wrote about the case on Truth Social.

"We are the only Country in the World STUPID enough to allow 'Birthright' Citizenship!" Trump said.

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That claim, which has been made multiple times by the administration, is not true. About 30 countries, mostly in the Americas, have birthright citizenship.

The Supreme Court likely won't issue a ruling on this case for several months, but judicial experts believe they will likely side against Trump.

The Trump administration would look to replace birthright citizenship with one where a child's status would be determined by their parents' citizenship.

Trump's Scottish-born mother became a US citizen in 1942, four years before he was born.

His father Fred was born to German immigrant parents.

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