President Trump Donald John TrumpBiden says voters should choose who nominates Supreme Court justice Trump, Biden will not shake hands at first debate due to COVID-19 Pelosi: Trump Supreme Court pick 'threatens' Affordable Care Act MORE argued Wednesday morning that children of undocumented immigrants born in the U.S. are not protected by the Constitution's 14th Amendment.

“So-called Birthright Citizenship, which costs our Country billions of dollars and is very unfair to our citizens, will be ended one way or the other. It is not covered by the 14th Amendment because of the words ‘subject to the jurisdiction thereof,’" Trump tweeted.

"Many legal scholars agree Harry Reid Harry Mason ReidSupreme Court fight pushes Senate toward brink The Supreme Court vacancy — yet another congressional food fight Trump seeks to turn around campaign with Supreme Court fight MORE was right in 1993, before he and the Democrats went insane and started with the Open Borders (which brings massive Crime) 'stuff.' Don’t forget the nasty term Anchor Babies. I will keep our Country safe. This case will be settled by the United States Supreme Court!" he added.

So-called Birthright Citizenship, which costs our Country billions of dollars and is very unfair to our citizens, will be ended one way or the other. It is not covered by the 14th Amendment because of the words “subject to the jurisdiction thereof.” Many legal scholars agree..... — Donald J. Trump (@realDonaldTrump) October 31, 2018

....Harry Reid was right in 1993, before he and the Democrats went insane and started with the Open Borders (which brings massive Crime) “stuff.” Don’t forget the nasty term Anchor Babies. I will keep our Country safe. This case will be settled by the United States Supreme Court! — Donald J. Trump (@realDonaldTrump) October 31, 2018

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Trump in a later tweet said that the world is using U.S. laws "to our detriment.

"They laugh at the Stupidity they see!" he added.

The World is using our laws to our detriment. They laugh at the Stupidity they see! — Donald J. Trump (@realDonaldTrump) October 31, 2018

Trump floated the idea of issuing an executive order banning birthright citizenship in an interview with Axios, which released a clip of the exchange Tuesday.

He was soon joined in support on Capitol Hill by some of his staunchest allies, such as Sen. Lindsey Graham Lindsey Olin GrahamHarris slams Trump's Supreme Court pick as an attempt to 'destroy the Affordable Care Act' Sunday shows preview: Lawmakers prepare for SCOTUS confirmation hearings before election Confirmation hearing for Trump's Supreme Court pick to start Oct. 12 MORE (R-S.C.).

Critics of the plan say it would violate the 14th Amendment, which states in part, “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.”

Opponents of birthright citizenship claim that “subject to the jurisdiction thereof” means only children of citizens should automatically get citizenship because their parents owe their allegiance to the U.S., while noncitizens do not.

While the Supreme Court has never ruled explicitly if the children of specifically undocumented immigrants are covered under the 14th Amendment’s protections, it wrote in 1898, “the 14th Amendment affirms the ancient and fundamental rule of citizenship by birth within the territory, in the allegiance and protection of the country, including all children here born of resident aliens.”

Trump has sought to thrust immigration into the center of the national discourse in the week before the midterm elections, believing debate surrounding the hot-button issue benefits Republicans. He is known for his hard stance on immigration and has slammed Democrats for wanting “open borders.”

Fox News on Tuesday reported that Republicans are using a 1993 speech in which then-Sen. Harry Reid (D-Nev.), who would go on to become Senate majority leader, said "no sane country" would "reward" the child of an undocumented immigrant with U.S. citizenship to justify its immigration push.

Updated at 11:32 a.m.