▶ Watch Video: DeSantis expected to contrast himself with Trump as campaign kicks off in Iowa

Former President Donald Trump on Tuesday pledged to challenge a long-standing interpretation of the U.S. Constitution in an attempt to end birthright citizenship for children of unauthorized immigrants if he defeats President Biden in the 2024 election.

If he secures a second presidential term, Trump said he would issue an executive order during his first day back at the White House in January 2025 instructing the federal government to deny citizenship to children with parents who are not American citizens or legal permanent residents. 

Under a decades-long interpretation of the Constitution, children born on U.S. soil are automatically bestowed American citizenship, even if their parents are not themselves citizens or legally present in the country. Some immigration hardliners have long criticized the policy, saying it encourages parents to come to the U.S. illegally. While he was in the White House, Trump repeatedly floated the idea of challenging the interpretation, but never took action. 

In his announcement Tuesday, Trump portrayed the move as part of a broader crackdown on unauthorized immigrants and asylum-seekers that he has promised if he returns to the White House. He has also vowed to launch the largest immigration roundup and deportation operation in U.S. history.

“My policy will choke off a major incentive for continued illegal immigration, deter more migrants from coming and encourage many of the aliens Joe Biden has unlawfully let into our country to go back to their home countries. They must go back,” Trump said in a video message on Tuesday.

If Trump wins the 2024 presidential election and follows through on his promise, the move to end birthright citizenship for children of immigrants living in the U.S. without legal permission is all but certain to face significant legal challenges.

The 14th Amendment of the Constitution, adopted following the Civil War, declares that all “persons born or naturalized in the United States” are “citizens of the United States and of the State wherein they reside.”

“Any executive action that a president might try to end birthright citizenship would be challenged in court and would be likely struck down as unconstitutional,” said Stephen Yale-Loehr, an immigration law professor at Cornell University.

While the move would likely not pass legal muster, Yale-Loehr added, it could be a beneficial campaign tactic for Mr. Trump, especially during the Republican primary.

“I think it’s pretty clear that, for political purposes, he thinks that this kind of announcement will appeal to his base. It shows that he has anti-immigration credentials. And most of his voters don’t know or don’t care about whether such an executive order would be legal,” Yale-Loehr said.

Florida Gov. Ron DeSantis, the 2024 Republican presidential candidate who is currently Trump’s closest challenger in the polls, has also sought to make immigration a top issue of his campaign. 

A measure championed by DeSantis that was recently passed by the Florida legislature will be among the strictest state immigration laws in American history. Among other things, it will invalidate driver’s licenses other states provide to unauthorized immigrants, require hospitals to document whether patients are in the country legally, fund efforts to relocate migrants to “sanctuary jurisdictions” and impose fines for employers who don’t verify the immigration status of workers. 

In addition to sharply criticizing the Biden administration’s handling of the record number of migrant crossings reported along the southern border in recent years, Trump and DeSantis have feuded over which candidate has the toughest immigration platform.

DeSantis recently accused Trump of supporting “amnesty” by endorsing a bipartisan proposal that would have traded border barrier and security funds in exchange for the legalization of some unauthorized immigrants, including those brought to the U.S. as children.