There’s a U.S. Second Circuit judge, Denny Chin, who might be able to set Donald Trump straight on his allegations against the district judge Gonzalo Curiel—but so could any second-year law student who has remained awake during professional-responsibility class.

Zero plus zero equals zero.

Most lawyers would call the 1998 case this lesson comes from, Macdraw Inc. v. CIT Equipment Financing, an “ordinary case”—one company agreed to help another finance a large sale of industrial equipment. The deal went south, the buyer went bankrupt, and the borrower sold the collateral. The lender, Macdraw, sued for its claimed share, and the case had dragged on for six years in a New York federal district court by the time Chin had to school Macdraw’s lawyers on legal ethics and judicial impartiality.

There was nothing ordinary about those lawyers. The lead attorney was Larry Klayman, the founder of the conservative advocacy group Judicial Watch and the force behind dozens of politically minded lawsuits, including a recent one claiming that the Obama Administration engineered the spread of Ebola to exterminate the “Caucasian race and Jewish-Christian religion.”

Eventually, Chin dismissed Klayman’s client’s case with a few choice words for the way counsel had conducted it. Not long after, the judge got a letter from Klayman and his co-counsel, Paul Orfanedes, asking a few “questions” about the judge’s Asian American background and mentioning another case they had brought against the Clinton administration. They then filed a brief questioning the judge’s impartiality:

Mr. Klayman and Mr. Orfanedes became concerned that because the Court was a recent appointee of President Clinton … and Mr. Klayman had been prominently mentioned in the media for his role in the Commerce Department case, which focused in part on the White House, the Democratic National Committee, John Huang, Melinda Yee, and other persons in the Asian and Asian–American communities, and because the lawsuit had elicited such angry responses from the White House, Democrats and the Asian–American community, that the Court might be angry at them and unable to be fair and impartial ...

In a written response, Chin noted that he hadn’t been aware of Klayman’s other lawsuit. As for the questions about his race, he said, “This sentiment is absurd and demeans me individually and the Court as a whole.”

He then lowered the boom. Klayman and Orfanedes were required to withdraw as counsel from the case and would not be permitted to appear in Chin’s court on any matter ever again. They would be required to show his opinion to any other judge in the district in any future case. The court clerk would also report the sanctions to every court where they held bar membership.

Klayman and Orfanedes recruited former U.S. Attorney General Ramsey Clark (the lawyer for, among others, Lyndon LaRouche, Slobodan Milošević, and the Branch Davidians) to appeal the sanctions. The Second Circuit briskly affirmed Chin’s order. “Courts have repeatedly held that matters such as race or ethnicity are improper bases for challenging a judge's impartiality,” wrote the chief judge, Ralph Winter, a Reagan appointee. “Nor should one charge that a judge is not impartial solely because an attorney is embroiled in a controversy with the administration that appointed the judge. … Finally, appointment by a particular administration and membership in a particular racial or ethnic group are in combination not grounds for questioning a judge's impartiality. Zero plus zero is zero.”

That equation is a good way to think legally about Donald Trump’s attack on Curiel, who is hearing a case against him as ordinary as Macdraw—a civil class action alleging Trump’s “university” was a scam aimed at defrauding its students by selling them worthless instruction.

Trump has now made an issue out of Curiel’s ethnicity and his appointment to the bench by the Obama administration. His ire was raised because the judge allowed the release of some documents from Trump University—documents that seem extremely damaging to Trump’s case. “The judge was appointed by Barack Obama,” Trump told a rally last week. “The judge, who happens to be, we believe, Mexican, which is great, I think that’s fine.” In an interview with The Wall Street Journal, Trump went on to say that Curiel’s “Mexican heritage”—he was born in Indiana—should disqualify him because “I’m building a wall. It’s an inherent conflict of interest.”

“If background or sex or race of each judge were ... sufficient grounds for removal, no judge on this court could hear this case.”

Curiel, as The New York Times noted, has faced down a Mexican drug cartel and is thus probably not intimidated by the likes of Trump. But Trump’s ugly tantrum does offer a chance to look at some ignorant misconceptions about judicial impartiality.

Start with former U.S. Attorney General Alberto Gonzales, who on Saturday spoke up on Trump’s behalf in The Washington Post. If Trump screams “smoke!” loudly enough, he suggested, we ought to start wondering whether—not saying there is, just raising the question—there might be fire. In Trumpian form, Gonzales said, “I am not judging whether Curiel is actually biased against Trump. Only he knows the answer to that question.” Gonzales didn’t mention there is no evidence of bias. After all, he’s just, you know, saying.

With similar primness, The Daily Caller noted, “Curiel served on the selection committee in 2014 for the La Raza Lawyers of San Diego Scholarship Fund. Six of seven of the recipients of these scholarships ranging from $1500 to $1600 were born in Central America. One of them, Ricardo Elorza, described himself as ‘undocumented.’” Curiel is a member of a group with La Raza in its name. It’s not the National Council of La Raza, as Trump has suggested, just a staid lawyers’ group; but still, that’s a Spanish word, pretty damning. He also appointed a lead class-action lawyer from a firm that has members who support Hillary Clinton. Of course, that appointment took place before anyone imagined Trump was a serious presidential candidate, but still, Gonzales said, “it might not be unreasonable for a defendant in Trump’s position to wonder who Curiel favors in the presidential election.”

“I wonder if this Latino judge doesn’t like me because I go around saying bad things about people like him” is actually not a “reasonable” thought for a litigant, and certainly not a legal argument for recusal. Trump’s lawyers, I suspect, know they risk sanctions if they make it.

“At least in the federal system, judges separate themselves from politics when going on the bench, and their life tenure reduces any felt reliance on political patrons,” wrote Winter, the judge in Macdraw. To overcome that presumption, anyone—a layperson or a lawyer—needs what is called “extrajudicial” evidence of actual bias. That is, not the fact that a judge is a Democrat, but that he or she expressed generalized bias to others, or spoke badly outside of court of the party or the lawyers. Absent that, a litigant has, as Winter said, zero.

A related misconception is that the impartiality of minority judges is inherently suspect. As David Graham noted, in the 1970s, this Trump-style claim of “inherent” bias was thrown at the great Leon Higginbotham, who rose to be chief judge of the Third Circuit. Higginbotham, an expert of the history of race and American law, crisply denied the motion:

By that standard, white judges will be permitted to keep the latitude they have enjoyed for centuries in discussing matters of intellectual substance, even issues of human rights and, because they are white, still be permitted to later decide specific factual situations involving the principles of human rights which they have discussed previously in a generalized fashion. But for black judges, defendants insist on a far more rigid standard, which would preclude black judges from ever discussing race relations even in the generalized fashion that other justices and judges have discussed issues of human rights.

Constance Baker Motley, the first female African American judge, faced a similar challenge in a 1975 sex-discrimination case. “[I]f background or sex or race of each judge were, by definition, sufficient grounds for removal,” she responded, “no judge on this court could hear this case.” Catholic and Mormon judges have also been challenged; Judge Michael Mukasey, an Orthodox Jew, was asked to step aside from a case against a Muslim defendant in 1994. Citing Higginbotham’s landmark opinion, he said that motion was “the same rancid wine in a different bottle.

Trump wine has always been a little off, and this vintage fairly reeks. At its rawest, the claim amounts to, “Who are you—African American, woman, Jews, ‘Mexican’—to judge a real citizen, a white man?” It’s no different, in essence, from the assertion of one Texas Ku Klux Klansman, being sued for harassing Asian American fishermen, that a female black judge should withdraw because “of the prejudice of ‘your people against the Klansmen.’”

The re-introduction of this crude, explicit racism into politics is repellent. More repellent yet, in a sense, is the effort now beginning—by figures like Gonzales, Joel Pollak of Breitbart, The Daily Caller, and other conservative outlets—to mainstream this dangerous deviancy.

It remains for the present to extend Winter’s equation to three terms. The Trump side has nothing. No law. No logic. No facts. In 2016, zero plus zero plus zero is even less than zero.