The Supreme Court is widely expected to strike down “race-conscious” college admissions policies in Students for Fair Admissions v. Harvard and Students for Fair Admissions v. University of North Carolina Chapel Hill. After listening to the oral arguments for the case on Monday, it’s easy to understand why: advocates for affirmative action from both schools have no end date or stated goal in mind. They claimed repeatedly that campus diversity depends on the use of race-conscious admissions, but refused to say when their campuses might reach optimal diversity or even what optimal diversity might look like.

Justice Samuel Alito pressed North Carolina Solicitor General Ryan Park on this latter point, asking Park when an applicant could rightly be considered a minority according to the University of North Carolina. If an applicant is half-black and half-white, can he claim to be black? Or what about an applicant whose great-grandmother was Native American? Can she claim to be Native American? 

Park responded by saying the school depends on self-reporting and generally trusts that what the applicant reports is the truth. 

Alito pressed forward: “Well, I identify as an American Indian because I’ve always been told that some ancestor back in the old days was an American Indian,” he said.

Park responded: “In that circumstance, it would be very unlikely that that person was telling the truth.”

But Park never explained how the school would go about determining whether such a claim was true, or what it would do if it turned out to be a lie. And that’s because there is no definitive definition of race, nor is there an agreed-upon standard by which to measure it—at least, not when it comes to college admissions. 

Park admitted as much later on in an exchange with Supreme Court Justice Brett Kavanaugh, who asked him how Middle Eastern applicants are supposed to identify themselves on the University of North Carolina’s applications since there isn’t a specific box for the Middle Eastern ethnicity. Park responded by saying the school’s applications allow applicants to specify their country of origin. 

“But if they honestly check one of the boxes, which one are they supposed to check?” Kavanaugh asked.

Park responded: “I—I do not—do not know the answer to that question. What I can say is that if a person from a Middle Eastern country self-discloses their country of origin, it would be considered in the same way that we consider any box that matches, you know, one of the boxes that’s available in the common application, which is it would be an individualized holistic analysis.”

There is, in fact, an answer to Kavanaugh’s question, though it only further serves to undercut the argument made by affirmative action advocates. According to the Education Department, people of Middle Eastern descent are supposed to check the “White” box on the Common App’s race question—even though most Middle Easterners do not fit inside the Anglo-Saxon category typically used to describe white people. Perhaps Park didn’t want to admit this since to do so would be to also admit that the vague racial categories used by colleges across the country force applicants into narrow boxes that don’t accurately reflect their backgrounds or experiences.

But the most revealing exchange during Monday’s arguments came when Justice Clarence Thomas asked Park to explain what exactly he means when he says “diversity.”

“I’ve heard the word ‘diversity’ quite a few times, and I don’t have a clue what it means,” said Thomas. “It seems to mean everything for everyone.”

Park responded by claiming the University of North Carolina understands diversity to be a “broadly diverse set of criteria that extends to all different backgrounds and perspectives and not solely limited to race.”

Thomas then pushed Park to cite specific educational benefits the school receives from using race-conscious admissions policies. Park claimed that the benefits include reduced “group think” and “more sustained disagreement and that leads to a more efficient outcome.”

But then Thomas cut to the core of the issue. If this case had been brought against a school during the Jim Crow era, he asked, and the school claimed that segregation yielded the same educational benefits that Park just described, would the University of North Carolina support such a discriminatory policy? Park was forced to admit that, of course, the school would not. 

And yet the University of North Carolina’s habit of factoring in the race of its applicants is just as discriminatory today as it was during Jim Crow. We’ve spent years trying to right the wrongs of the past and build a colorblind society in which every person, regardless of ethnicity, is treated equally. Colleges’ continued use of race-conscious admissions policies is an insult to that effort and will only lead to more inequality, not less.

Time will tell if the Supreme Court agrees.