IN AUGUST 2015, Donald Trump sat down with Bill O'Reilly to talk about two central campaign promises: the mass deportation of 11 million undocumented immigrants and the rollback of birthright citizenship. "Our country is going to hell," Trump said. "We have to start a process where we take back our country." O'Reilly found the plan ridiculous.

Such a colossal and expensive undertaking, the conservative host said, was just "not going to happen." Perhaps the most obvious reason, he said, was the 14th Amendment. "If you're born here, you're an American-period! Period!" O'Reilly almost screamed. "You can't kick Americans out."

Trump was unconvinced. "Many lawyers are saying that's not the way it is," he insisted. The president's view then, and now, is that the American children of undocumented immigrants should not be entitled to automatic citizenship-and, if prompted to weigh in, the courts would agree with him: "A lot of people don't think they are."

The first Trump administration didn't test this theory. The second one likely will. In a May 2023 campaign video, Trump asserted that automatic citizenship for the children of undocumented immigrants "is based on a historical myth and a willful misinterpretation of the law." This time, Trump campaigned on a more fleshed-out plan to "explain the clear meaning of the 14th Amendment," and to take executive action to instruct federal agencies to deny passports and Social Security numbers to children born to parents without citizenship or legal residence.