Donald Trump’s repeated demands that U.S. District Judge Gonzalo Curiel, who is of Mexican heritage, recuse himself from the fraud cases against Trump University, have no legal or constitutional merit.

Indeed, they draw from a long-standing but failed legal playbook used against minority judges.

Trump argues that his campaign’s hardline position on illegal immigration—namely, the presumptive Republican nominee’s repeated promise to seal off the the border between Mexico and the U.S.—creates an “absolute conflict” with the judge, who Trump described as a “Mexican” appointed by President Obama. Curiel was born in Indiana; his parents were Mexican immigrants.

“I’m building a wall,” Trump told the Wall Street Journal Thursday. “It’s an inherent conflict of interest.”

Legal scholars roll their eyes at Trump’s line of attack. There is nothing in the U.S. Constitution—and no U.S. law, regulation or code of judicial conduct—that suggests that a judge must recuse him or herself because of race, gender, ethnicity, sexual preference, or any other aspect of someone’s personal identity. After all, no judge is free from these categories.

“The notion that a judge has to recuse him or herself because of racial makeup, religious background, gender or ethnicity—it’s all just nonsense,” Stephen Burbank, a professor for the administration of justice at the University of Pennsylvania Law School told TIME. “It’s absolute nonsense.”

Arthur Hellman, an expert on federal judicial ethics at the University of Pittsburgh’s law school said that if that were indeed a standard, it would result “in chaos.” If a judge could be forced to step aside merely because of membership in a minority group of some kind, judges would constantly be removed from cases, he told TIME.

U.S. Supreme Court justices Clarence Thomas and Sonia Sotomayor could be feasibly barred from weighing in on cases concerning civil rights. Chief Justice John Roberts, a Catholic, could be forced to recuse himself from any case having to do with religion.

The idea that judges must put aside their personal identities and appeal instead to what’s known as “judicial temperament,” Hellman explained, has long been the bedrock of the U.S. judicial system.

That idea was solidified in 1974 when Judge Leon Higginbotham, an African-American district judge, refused to recuse himself from a case that had to do with racial discrimination. Higginbotham, who was himself regularly the object of racial bias, argued that his personal experience should not be disqualifying and later issued what is now considered a universally accepted opinion on the matter.