The Constitution guarantees citizenship to nearly everyone born in the US. Trump wants to take that away.

Ending birthright citizenship has been on President-elect Donald Trump’s wish list for years, and he’s pledged to kill it once and for all in his next term. But ending it may not be as easy as he’s promised.

Under a longstanding interpretation of the Constitution and federal law, children born in the US automatically become American citizens, even if their parents are undocumented. Trump, however, has promised that, “On day one of my new term in office, I will sign an executive order making clear to federal agencies that under the correct interpretation of the law, going forward, the children of illegal immigrants will not receive automatic US citizenship.”

Specifically, that executive order would mandate that at least one parent must be a US citizen or green card holder for their child to qualify for automatic citizenship. Federal agencies would be directed to deny passports, Social Security numbers, and public benefits to children with two undocumented parents.

The executive order would almost certainly be challenged in court. Though it’s impossible to say what the Supreme Court may ultimately decide, history and precedent isn’t on Trump’s side.

“I think that birthright citizenship is such a bedrock principle of American law that of all the things on the Trump agenda, this is the one least likely to be successful,” said Hiroshi Motomura, a professor at UCLA School of Law.

Trump has framed the policy as a solution to “birth tourism” — when pregnant people travel to the US to give birth in order to secure US citizenship for their child — and a means of removing a pull factor for unauthorized immigration, which has sharply declined at the southern border in 2024. The policy also reflects Trump’s longtime efforts to assert a particular vision of what it means to be American in an era when the US’s white population is declining. In his first term, he reportedly eschewed immigration from “shithole countries,” referring to Haiti and African countries. And he has more recently claimed that immigrants are “poisoning the blood” of the country.

It’s not clear how many people could be impacted by the policy. However, about 5.5 million American citizen children currently live in mixed-status households, some of them with two undocumented parents, which would have made them ineligible for automatic US citizenship under Trump’s proposed policy. That suggests that the affected population of future children born in the US could be large.

What the law says

The prevailing belief among legal experts is that ending birthright citizenship would require a constitutional amendment, that there is not enough support in Congress to pass one, and that Trump’s proposed executive order would not hold up in court.

“President Trump cannot do this,” said Erwin Chemerinsky, the dean at Berkeley Law school. “President Trump cannot change the Constitution by executive order.”

He said that ending birthright citizenship by executive order contravenes the 14th Amendment, which was adopted after the Civil War to ensure that formerly enslaved people would be considered US citizens.

The 14th Amendment states: “All persons born or naturalized in the United States, and subject to the jurisdiction thereof, are citizens of the United States.”

Chemerinsky said that this has “always been understood to mean that all born in the United States (or naturalized as citizens) are United States citizens,” in addition to any individuals under US jurisdiction abroad, such as children born to US military personnel in foreign countries. The phrase “subject to the jurisdiction thereof” was intended to exclude only Native Americans born on tribal land as well as children of enemy occupiers and foreign diplomats.

The Supreme Court’s 1898 decision in United States v. Wong Kim Ark “makes clear that those born in the United States are citizens,” Chemerinsky added. That case concerned a child born in California to Chinese immigrants who were lawful permanent residents of the US. At the time, no Chinese citizens were allowed to become naturalized US citizens under the Chinese Exclusion Acts. The court ruled that the child was a US citizen because he was born in the US, even though his parents were noncitizens.

Can Trump ban birthright citizenship anyway?

Right-wing immigration hawks have argued that the “subject to the jurisdiction thereof” clause ought to be interpreted differently to exclude children of unauthorized immigrants from the benefits of automatic citizenship. The clause, they argue, was meant to exclude anyone who had any loyalties to a foreign power, including citizens of other countries.

But even some of Trump’s allies — including Mark Krikorian, director of the Center for Immigration Studies, an anti-immigrant think tank — appear to acknowledge that he would face an uphill battle in court to realize his plan.

“I think it would be immediately challenged in the courts, and I think that the challenge would have all of the history and the origins of the statute behind it,” Motomura said. “I can’t predict what any court will actually do, but I think the historical record is so clear.”

Still, if Trump succeeds in enacting his executive order, its impact would be far-reaching. Birthright citizenship has served as an “engine of integration” for immigrant populations in the US, and ending it would also undermine America’s cultural identity as an “inclusive immigrant society,” Motomura said, adding that it would hit people of Mexican and Central American origin the hardest.

“That aspect can’t be ignored,” Motomura said. “It’s the resurrection of the use of US citizenship rules with a real racial impact, and I think an intentional racial impact.”