Picking up on an argument gaining currency on the right in recent years (it's been around for decades, though Iowa Rep. Steve King has given it fresh prominence), Trump said in an interview with the outlet Axios that although most people think birthright citizenship is enshrined in the Constitution, he's learned that it is not, and he can end it with the stroke of his pen.
"It was always told to me that you need a constitutional amendment. Guess what? You don't," Trump told Axios' Jonathan Swan. "You can definitely do it with an act of Congress, but now, they're saying I can do it just with an executive order." He did not say who "they" were.
By way of justification, Trump scoffed at the notion of citizenship by birth, although it's a concept that has been affirmed throughout the nation's history, by courts since at least 1844, and by the Supreme Court in 1898.
"How ridiculous -- we're the only country in the world where a person comes in, has a baby, and the baby is essentially a citizen of the United States for 85 years with all those benefits," Trump said. "It's ridiculous. It's ridiculous, and it has to end."
Here's where Trump might want to consult Reverdy Johnson. Johnson was co-counsel on the case in 1857 that denied Dred Scott and his family freedom, declared that African Americans could not be citizens, and all but ended any possible political resolution to slavery.
Johnson went on to be a Democratic senator from Maryland during the Civil War. He opposed abolition until 1864, when he supported the 13th Amendment that finally ended slavery. The 14th Amendment, however, went too far for his tastes, not just in granting citizenship to all black Americans, but enshrining birthright citizenship in the Constitution.
He was among opponents who tried dissuade backers of the amendment by pointing out people who would become citizens that other senators regarded as undesirable, particularly Native Americans. Johnson pointed to the deliberate exclusion of indigenous people in the Civil Rights Act of 1866 that had passed just a few months earlier. It declared as citizens "all persons born in the United States and not subject to any foreign power, excluding Indians not taxed."
The Citizenship Clause only says, "All persons born or naturalized in the United States, and subject to the jurisdiction thereof, are citizens of the United States." Its supporters, who agreed Indians should not be citizens, argued the native peoples had long been deemed members of their own nations, therefore effectively subject to their own foreign power.
But Johnson raised the extremely broad nature of the clause, noting the United States possessed the power to do whatever it wanted to Indians in its territory, regardless of treaties. "They are a part of the people of the United States, and independent of the manner with which we have been dealing with them it would seem to follow necessarily that they are subject to the jurisdiction of the United States, as is anybody else who may be born within the limits of the United States," he argued on the Senate floor on May 30, 1866.
Johnson lost the argument, but was clear in his understanding that "all persons born" meant pretty much almost all persons.
Trump appears to have gotten his idea from some hard-right conservatives such as King, who have been trying to revise the century-and-a-half-old understanding of the Citizenship Clause. They often cite the words of Sen. Jacob Howard, of Michigan, who wrote the version of the clause that passed, as evidence that immigrants were meant to be left out.
“This will not, of course, include persons born in the United States who are foreigners, aliens, who belong to the families of ambassadors or foreign ministers accredited to the Government of the United States, but will include every other class of persons," Howard said.
King and others point to the word "aliens," in particular, but what they ignore is that Howard's statement echoes the English common law standards for citizenship in place at the time, which were that the fact of birth confers citizenship unless the birth is to a diplomat from another sovereign state, or someone who's part of another nation's invading army.
Indeed, Reverdy Johnson was not alone among senators opposed to the 14th Amendment who tried to defeat it by raising specters of undesirable, child-bearing immigrant invaders that sound like templates for President Trump's current daily tweets about caravans of "very bad thugs and gang members" heading for the border.
Sen. Edgar Cowan, of Pennsylvania, expressed invasion-like scenarios repeatedly, with a special focus in his own state on Gypsies. He made them sound like the apocryphal welfare queens of the 1980s.
"These people live in the country and are born in the country. They infest society everywhere. They impose on the simple and weak everywhere. Are those people, by a constitutional amendment, to be put out of the reach of the state in which they live?" Cowan said. "If the mere fact of being born confers that right, then they will have it; and I think it will be mischievous."
He used Trump-like language against Chinese immigrants to the West Coast.
"I have supposed, further, that it was essential to the existence of society itself, and particularly essential to the existence of a free State, that it should have the power, not only of declaring who should exercise political power within its boundaries, but that if it were overrun by another and a different race, it would have the right to expel them," Cowan said. Among those races were Mongols, Hottentots, cannibals and Australians. "Is it proposed that the people of California are to remain quiescent while they are overrun by a flood of immigration by the Mongol race? Are they to be immigrated out of house and home by Chinese?"
Cowan directly asked Illinois Sen. Lyman Trumbull, the chairman of the Judiciary Committee that crafted the 14th Amendment, “whether it will not have the effect of naturalizing the children of Chinese and Gypsies born in this country?”
Trumbull was unequivocal about what birthright citizenship meant in his answer. "Undoubtedly," he said during floor debate on Jan. 30, 1866.
Similarly, When Cowan raised objections again in May, a week before the Senate passed the amendment, California's Sen. John Conness was not alarmed at the prospect of Chinese immigrants' children becoming citizens. "We have declared that by law," he said, referring to the Civil Rights Act. "Now it is proposed to include the same provision in the fundamental instrument of the nation. I am in favor of doing so."
Trumbull and Conness were, of course, on the winning side, and courts have seen the issue their way ever since.
That hasn't stopped the growing anti-birthright argument that Trump just embraced. But 14th Amendment opponents like Reverdy Johnson and Edgar Cowan were clear on what the amendment and clause did. They didn't like it, but they didn't deny it, either, as Trump and right-wing conservatives do now. They just wanted to limit it as much as possible.
"Before we assert broadly that everybody who shall be born in the United States shall be taken to be a citizen of the United States, we ought to exclude others besides Indians not taxed, because I look upon Indians not taxed as being much less pestiferous to society than I look upon Gypsies," Cowan said.
If Trump does not pay attention to the words of Reverdy Johnson now, and he issues an executive order against birthright citizenship, it is almost certain that he will hear them again in the Supreme Court.