Seeking to shore up support for Republicans ahead of the congressional elections next week, Trump told the Axios news website he would try to end the right of citizenship for US-born children of non-citizens and illegal immigrants.
The president said in an interview published on Tuesday that he would make the move through an executive order, likely prompting a legal fight.
The right of citizenship is granted to US-born children under the 14th Amendment of the Constitution, which cannot be changed by the president.
It was unclear what specific action he would pursue, and Trump gave no details. Representatives for the White House did not respond to a request for comment.
“This is blatantly unconstitutional,” Omar Jadwat, head of the ACLU Immigrants’ Rights Project told Reuters. “The president obviously cannot overturn the Constitution by executive order. The notion that he would even try is absurd.”
Changing an amendment in the Constitution would require the support of two-thirds of the US House of Representatives and the Senate and the backing of three-fourths of US state legislatures at a constitutional convention.
But Trump said he has talked to his legal counsel and was advised he could enact the change on his own. Asked about the dispute over such presidential powers, Trump said stood by his comments.
“It’s in the process. It’ll happen,” he told Axios in the interview, which will air in full on the HBO pay cable channel on Sunday.
Some conservatives have long pushed for an end to the guarantee of birthright citizenship, a view Trump echoed.
“It’s ridiculous. It’s ridiculous. And it has to end,” Trump told Axios.
Trump, whose hard-line immigration stance helped him win the White House, has seized on the issue in recent weeks in the run-up to the Nov. 6 vote that has Americans sharply divided and grappling with race and national identity.
His latest comments also come after the deadliest attack on Jews in US history on Saturday and a series of bombs sent to top Democrats and other Trump critics last week.
The 14th Amendment allows for “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.”
A legal challenge would prompt the nation’s courts to weigh in on what would be one of the most sweeping moves of the Trump administration. It has already targeted immigration through a travel ban from several Muslim-majority countries, child-parent separations for migrants, refugee policies and other actions.
In 1898, the US Supreme Court reaffirmed the right of citizenship to children born to legal permanent residents.
But conservatives say it should not apply to everyone, including immigrants in the country illegally or those with temporary legal status, Axios reported.
Immigrant advocacy organizations are gearing up for a legal fight against any move to end birthright citizenship, said Greisa Martinez Rosas, deputy director of United We Dream, a national immigrant youth group.
But she noted that the Trump administration has managed to notch legal victories for its immigration policies. “He has done a lot of things we thought he was unable to do,” she said.
“We know that it’s unconstitutional but what I think in this moment what is most important is for people to organize and vote.”
Democrats and other critics have condemned the president’s rhetoric on immigration as inflammatory, urging Trump to tone down his language and calling on voters to use the elections as a way to reject such policies.
US Senator Chris Coons, a Democrat on the Senate Foreign Relations Committee, told MSNBC that Trump “was driving a false narrative on immigration” in many ways to stoke fear and turn it into an election issue.
On Monday, the administration moved to send more than 5,200 troops to help secure the border with Mexico as a caravan of Central American migrants, mostly on foot, makes its way there, although it is unclear how many would arrive at the border or when.