Hunched forward in his chair, his fingertips and thumbs forming a familiar diamond shape, Donald Trump seemed to anticipate the question that Axios’s Jonathan Swan was about to ask him. “On immigration, some legal scholars believe you can get rid of birthright citizenship without changing the Constitution—” Swan began, before Trump cut him off gingerly. “With an executive order,” he interjected. “Exactly,” Swan replied. “Have you thought about that?” The president didn’t miss a beat. “Yes.”

The video teaser of the interview, which will appear in Axios’s forthcoming documentary news series on HBO, erupted in the middle of a news cycle driven by Trump’s inflammatory comments regarding immigration—his decision to dispatch the military to the U.S.-Mexico border, relentless fear-mongering over a migrant caravan of Central American “invaders,” and a white-supremacist terror attack inspired by Jewish aid for refugees. Trump, who is presiding over a midterm election next week that could determine control of the House, has been betting that a hard-line message on immigration will drive G.O.P. turnout. Yet even for a party that has largely aligned itself with the president’s nationalist rhetoric, what Trump proposed was radical and largely without precedent. “It was always told to me that you needed a constitutional amendment. Guess what? You don’t,” the president continued in his conversation with 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.” His subsequent claim—that the U.S. is the only country that bestows citizenship upon anyone born within its jurisdiction—was false, but the racial anxiety he was tapping into is real. “[A] person comes in, has a baby, and the baby is essentially a citizen of the United States . . . with all of those benefits. It’s ridiculous. It’s ridiculous. And it has to end.”

The idea of revoking birthright citizenship has wended its way through Washington for years. Democrat Harry Reid, former Senate Majority Leader, proposed revoking birthright citizenship in 1993, before repeatedly apologizing for it. (“I didn’t understand the issue. I’m embarrassed that I made such a proposal,” he told the Las Vegas Review-Journal.) On the right, fear of “anchor babies” has been exploited politically by even moderates such as Jeb Bush, who invoked the issue in 2015. But Trump’s decisive claim that he could get end birthright citizenship with the stroke of a pen caused critics to drop their jaws. “He obviously cannot do that,” said House Speaker Paul Ryan, noting the intractable reality: birthright citizenship has been enshrined in the 14th Amendment for 150 years and would require no less than an act of Congress or a Supreme Court challenge to knock it down, an endeavor the vast majority of legal scholars consider impossible.

Regardless of whether it is a midterm stunt, Trump’s fever dream has very real origins in the scholarship of the Claremont Institute, a right-wing think tank based in Southern California—the front line, incidentally, of illegal border crossings. The current legal argument for revoking birthright citizenship, which had percolated on the left and right in the 90s, began gaining traction in 2006, when John C. Eastman, a Claremont Institute affiliate who is a professor at Chapman University’s Fowler School of Law, published an article for the Heritage Foundation laying out a three-point argument to challenge the authority of birthright citizenship. First, according to Eastman, at the time of the 1866 Civil Rights Act, children born to foreigners were “not entitled to claim the birthright citizenship” provided by the act. Since the Act eventually became the backbone of the 14th Amendment, therefore, the original interpretation of citizenship should take precedence. Second, he argued the reading of the 14th Amendment—that birthright citizenship can be bestowed upon anyone who is “subject to the jurisdiction” of the United States—was overbroad; in Eastman’s reading, citizenship can only be bestowed upon people with “total and exclusive allegiance” to the country. If a child’s parents had not pledged fealty to America, either by becoming full citizens or establishing permanent residence, their loyalty to the Constitution would, by all definitions, be as temporary as that of their parents. (The common legal interpretation of ”subject to the jurisdiction” is that anyone who enters the country, no matter how briefly, are subject to U.S. laws.) Finally, he wrote, the policy was a medieval remnant inconsistent with the Founding and the notion that Americans need consent to be governed: “This consent must be present, either explicitly or tacitly, not just in the formation of the government, but also in the ongoing decision whether to embrace others within the social compact of the particular people.”

The next year, Edward J. Erler, a Claremont scholar and one of the original thinkers on birthright issues, published a bookwith two colleagues examining what reviewer and Hoover Institution fellow Victor Davis Hanson deemed the problem of “massive illegal immigration from Mexico” for the American identity: “How did the founders and their successors deal with problems of being an American, and what are the effects of massive noncompliance with the laws of the United States?” Apart from several additional treatises they published, however, the idea never caught on with the rest of the conservative legal community. “It’s certainly in the idea of originalism, in that it relies that you understand the text at the time it was written, [but] there are a lot of people, even in that broadly conservative camp, that just reject it,” said Corey Brettschneider,professor of political science and public policy at Brown University, and the recent author of The Oath and the Office: A Guide to the Constitution for Future Presidents. “There are a couple of scholars that are pushing it, but it’s not a mainstream view even in conservative circles. That’s because it’s kind of wacky.”

Over time, Eastman and Erler’s legal arguments were adopted in Washington as part of various efforts to curb illegal immigration. In 2010, a small group of Republican senators, including Jeff Sessions, Mitch McConnell, and John McCain, floated the idea of holding hearings on the issue; Wisconsin Governor Scott Walker proposed a similar plan in 2015. Most conservative figures in Congress, to say nothing of the pro-immigration donor class, balked. But when Trump launched his unconventional, nativist-pandering campaign, legal birthrightists held out hope that he could indeed become their political vessel to revoke the law. “Political pundits believe that Trump should not press such divisive issues as immigration and citizenship. It is clear, however, that he has struck a popular chord—and touched an important issue that should be debated no matter how divisive,” Erler wrote in National Review in August 2015. At the same time, Erler acknowledged foreseeable roadblocks. “Republicans want cheap and exploitable labor and Democrats want future voters,” he said.

By early 2016, Stephen Miller was forcefully pushing for an end to the birthright privilege, calling it the linchpin in the administration’s immigration policies. “Birthright citizenship really is the ultimate magnet for illegal immigration,” he told the Daily Caller that February, outlining the traditional conservative fears of chain migration, anchor children, and the decreased likelihood of deportation. “[It’s] an open, worldwide invitation to ignore America’s immigration laws and an absolute perversion, misinterpretation, misapplication of the 14th Amendment.” Miller then suggested that Trump could do it more easily than the media or legal scholars imagined: “You could do it through a variety of different means, whether it be legislatively, whether it be through potential guidance that’s issued.”

Plans to revoke birthright citizenship were shelved during the first year of the Trump administration, beset by internal drama, failed policies, and the Russia investigation. But they were not abandoned. Less than four months ago, the idea began to pick up steam once again when Michael Anton, a Claremont writer, former Trump National Security Council spokesman, and author of the infamous Flight 93 essay, argued for the end of birthright citizenship in The Washington Post, drawing largely from the Claremont argument. He then laid down the supposition that Trump could actually do it via executive order—if not to enforce the concept, then to eventually enshrine it in legal precedent. “An executive order could specify to federal agencies that the children of non-citizens are not citizens,” Anton wrote. “Such an order would, of course, immediately be challenged in the courts. But officers in all three branches of government—the president no less than judges—take similar oaths to defend the Constitution. Why shouldn’t the president act to defend the clear meaning of the 14th Amendment?”

According to Axios, the Trump administration had been quietly working on this policy for months, and Trump himself was surprised that Swan brought it up in their interview. (“I didn’t think anybody knew that but me. I thought I was the only one.”) But the revelation of the plan—only weeks away from the midterm election, and in the middle of Trump’s furious posturing on the migrant caravan winding its way to the southern border—immediately won plaudits among several of Trump’s allies, with Lindsey Graham announcing that he was completely on board. More sober-minded Republicans told Politico that they opposed Trump taking action via executive order, and would perhaps try to tailor the breadth of the amendment’s application in Congress. Nevertheless, ending birthright citizenship unilaterally, they concurred, was a bad idea. “As a conservative, I’m a believer in following the plain text of the Constitution, and I think in this case the 14th Amendment is pretty clear, and that would involve a very, very lengthy constitutional process,” said Ryan. “But where we obviously totally agree with the president is getting at the root issue here, which is unchecked illegal immigration.”

The Talmudic ponderings of Congress, however, may be less important than the energy this will automatically inject into the election—not just for Democrats enraged about Trump’s treatment of illegal immigrants, but also for conservatives prioritizing border control. Indeed, if a talk Erler delivered in April at Hillsdale College is any indication, birthright citizenship is only one facet of the great threat of political correctness, progressive equalization, and the horrors of plurality looming over the American experiment. “Greater diversity means inevitably that we have less in common, and the more we encourage diversity the less we honor the common good,” he said at the time, calling multiculturalism “a solvent that dissolves the unity and cohesiveness of a nation.” He condemned Republicans for caving so quickly to any accusations of racism, sexism, classism, and homophobia. “Only President Trump seems undeterred by the tyrannous threat that rests at the core of political correctness,” he explained.