Washington DC - President Donald Trump launched his in an unhinged social media post that saw him attack "dumb judges and justices."

"Birthright Citizenship is not about rich people from China, and the rest of the World, who want their children, and hundreds of thousands more, FOR PAY, to ridiculously become citizens of the United States of America," Trump wrote in a Monday post to Truth Social.

"It is about the BABIES OF SLAVES!" he raged on. "We are the only Country in the World that dignifies this subject with even discussion. Look at the dates of this long ago legislation – THE EXACT END OF THE CIVIL WAR!"

"The World is getting rich selling citizenships to our Country, while at the same time laughing at how STUPID our US Court System has become (TARIFFS!). 'Dumb Judges and Justices will not a great Country make!'"

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Trump's latest meltdown comes as the Supreme Court is set to on Wednesday debate the legality of his administration's attempts to gut birthright citizenship laws.

Under the US Constitution's 14th Amendment, citizenship is given to "all persons born or naturalized in the United States, and subject to the jurisdiction thereof."

The only exemption to the rule has historically been the children of diplomats, but on the first day of his second administration, Trump signed an executive order limiting birthright citizenship for children born into undocumented migrant families.

Over the last year, the executive order has been challenged in numerous lower courts, before being referred to the US Supreme Court.

Speaking to USA Today, ACLU Immigrants Rights Project lawyer Cody Wofsy warned that if the order is upheld it would "signal a kind of open season on questioning the citizenship of other Americans."