From mass deportations, to torture and waterboarding, to dipping bullets in pig’s blood, Donald Trump is systematically redefining what is acceptable to say in American politics and perhaps eventually what is acceptable to do in American government. Election year 2016 is coming to seem like a remake of Eugène Ionesco’s play Rhinoceros, a surreal cautionary tale in which ordinary people, one by one, give up their humanity to the twin fevers of totalitarianism and rage.

Trump’s challenge to the U.S. Constitution is only one subchapter of that story; but the damage he is doing is real, and he’s not finished yet.

Consider that last weekend, Trump began to deploy his birther libel—first wheeled out against Barack Obama and then Ted Cruz—against Marco Rubio. His claims are only increasing in scope. Obama, Trump claimed, was not born in the United States. (He was.) Cruz was born (to an American citizen mother) in Canada. Trump says that means he’s not a natural-born citizen. (He is.) No one questions that Rubio was born in the United States. His parents were lawful permanent residents. The Constitution, on this point at least, is blessedly clear. To be born in the United States is to be born a citizen. Trump doesn’t question that. Not quite. Not yet. But late last week, he retweeted a supporter who suggested that Rubio is ineligible for the White House. When George Stephanopoulos asked him why he had done that, Trump responded: “Because I’m not sure. I mean, let people make their own determination.”

This is the way that Trump insinuates lies and libels into the discussion. It’s not me, he feigns, others have questions about Rubio, I’m just saying it could be a problem, and maybe we should look into it. Similarly, after repeating a supporter’s invective against Cruz, Trump shrugs: Hey, I didn’t make the indecent and sexist comment about Cruz. What can I do? My supporters are passionate. But that was just the start. By the Iowa caucuses, he was calling the Texas senator “the Canadian anchor baby.” Rubio can expect the same treatment.

I find no merit in the claims that Cruz isn’t eligible. First, the “legal principles that prevailed in the 1780s and ’90s”—which the Harvard Law professor Laurence Tribe has used against Cruz—don’t support the idea that an “originalist” judge would find Cruz ineligible. At any rate, it’s irrelevant; under the Constitution, citizenship is regulated by Congress, and the statutes in effect at the time Cruz was born leave no room for doubt. He is a born citizen, as eligible as any other to run for the presidency. The Constitution leaves many things up to Congress, and under the naturalization clause, one of them is citizenship. Beyond that, Dan Brown-style archeology is not a proper tool of constitutional interpretation, and pretending it is just emboldens the far-right’s outlandish claims about “original intent” in contexts like birthright citizenship and public land ownership. Trump and his claque are now moving the goalpost again, and the weak response fom constitutional scholars to the Cruz smear will make it harder to refute Trump’s new claim.

Tribe, who elevated Trump’s anti-Cruz rhetoric with an op-ed in The Boston Globe on January 11, instead muddied the waters. His insinuations themselves were positively Trumpian: I myself of course don’t doubt the senator’s eligibility. I’m just saying, “the kind of judge Cruz says he admires and would appoint to the Supreme Court” is also the kind of judge who would argue that “Cruz ironically wouldn’t be eligible” to become president. Tribe cites no real evidence for this claim. In fact, the op-ed itself could be seen as a kind of humorless academic prank:

When Cruz was my constitutional law student at Harvard, he aced the course after making a big point of opposing my views in class—arguing stridently for sticking with the “original meaning” against the idea of a more elastic “living Constitution” whenever such ideas came up...At least he was consistent in those days. Now, he seems to be a fair weather originalist, abandoning that method’s narrow constraints when it suits his ambition.

Having a foil like Cruz in class must have been frustrating. But Tribe’s didn’t produce any real evidence to support his claim that Cruz-style “originalism” would bar him from the presidency.  Trump himself has now dropped Tribe’s name in public appearances and debates to legitimize his own hollow assertions. And Tribe is not the only prominent academic who treated the Cruz birther issue seriously. As a result, now that Trump is zeroing in on Rubio, he can wield these  academic dalliances with the Cruz claim to cloud the mendacity of his new claim. It’s not coincidental that the targets of these birther libels are the first African American president and the first two credible Latino presidential candidates. Trump has also endorsed the indefensible claim that American-born children of undocumented aliens are not covered by the Fourteenth Amendment’s guarantee of birthright citizenship. The Rubio libel now extends that claim to include lawful aliens. The Constitution is clear; but enough mud can obscure any truth—and it’s flying now.

In much of the public mind, American citizenship is being redefined into a matter of race and blood, apparently as part of the nostalgia for an imagined golden era of racial, religious, and sexual exclusion. Worse, people who know better seem to be unable to resist playing the roles Trump assigns them in his sinister charade. Television hosts like Joe Scarborough and Mika Brezinzki embrace Trump with toothless questions, and Republican Party leaders are slowly capitulating to him as their party’s nominee. But academics should resist Trump’s knowledge corruption, whether it’s about climate change or the Constitution.

History will not be kind to those who should be the keepers of our ideals, but who instead are turning into rhinoceroses before the public’s eyes.