President Donald Trump on Tuesday revealed his desire to end birthright citizenship for American-born children of illegal immigrants and other non-U.S.-citizens.

Birthright citizenship refers to the idea that anyone born on U.S. soil is automatically a citizen. Trump’s announcement marks the latest in a series of hardline immigration efforts his administration has undertaken in recent months. The president first made his comments in an interview with Axios, which was released on Tuesday.

Many political pundits and legal experts have already said Trump’s intention could be potentially regarded as unconstitutional. Approximately 150 years ago, the U.S. Constitution was amended to include the phrase: “All persons born or naturalized in the United States and subject to the jurisdiction thereof, are citizens of the United States.” This is found in the 14th Amendment.

Trump did not specify when his proposal would be signed or take effect. This comes after the president, several prominent Republican lawmakers and conservative media outlets have spread fear about a large caravan of Hispanic migrants approaching the U.S. southern border. Trump has already ordered 5,200 military troops to the border to oversee the issue.

Trump recently claimed that “we’re the only country in the world where a person comes in and has a baby, and the baby is essentially a citizen of the United States for 85 years with all of those benefits.” However, a 2010 report from the Center for Immigration Studies revealed that 30 nations offered birthright citizenship at the time.

SLIDESHOW: DONALD TRUMP’S 30 CRAZIEST TWEETS

In a 2016 survey, the Pew Research Center discovered that births to “unauthorized immigrants’ were decreasing over the past decade and accounted for approximately a third of births to foreign-born mothers in the United States in 2014. Around 275,000 such babies were born that year, only 7 percent of all births in the nation in 2014.

Early Tuesday, the American Civil Liberties Union blasted Trump’s statements.

“The President cannot erase the Constitution with an executive order, and the 14th Amendment’s citizenship guarantee is clear,” Omar Jadwat, director of the ACLU’s Immigrants’ Rights Project, said according to CNN. “This is a transparent and blatantly unconstitutional attempt to sow division and fan the flames of anti-immigrant hatred in the days ahead of the midterms.”

Sen. Mark Warner, a Democrat from Virginia, commented on Trump’s proposal in an interview with CNN.

“This notion that he can simply violate the Constitution by executive order, let’s face it, no serious legal scholar thinks that’s real,” said Warner.

He continued: “This is simply an attempt for Donald Trump, who wants to do anything possible to bring back fears around immigration, to use that as a political tool in this last week before the election. This is again, where a President’s words matter. The Constitution is quite clear that no one, including the President of the United States, is above the law.”