The Supreme Court decided one year ago that racial preferences at public universities are legal, as long as they aren’t too mechanically applied. But this has proved cold comfort to affirmative action supporters besieged by evidence that preferences can’t deliver the results desired. With the constitutional issue resolved, Americans are asking whether affirmative action helps students in the first place.

Just what is affirmative action supposed to do? Educators trumpet the virtues of “diverse” campuses, but their enthusiasm dates suspiciously to a 1972 court decision suggesting diversity as a legal justification for preferences.

Ordinary Americans are more practical. Those sympathetic to affirmative action assume that it offers concrete benefits to disadvantaged students. They hope that preferences will narrow our nation’s painful racial divide along such metrics as income, literacy, homeownership and health.

But affirmative action in this sense is a myth. Admissions preferences do not offer practical empowerment to struggling citizens. They do not bridge society’s racial chasms. They do not address real social problems.

For one thing, affirmative action does not send more minorities to college. Most four-year colleges and universities in America are not selective; they take anyone with a standard high school education and a Pell grant. This means that race-based preferences are relevant only to the 20–30 percent of American colleges that enjoy substantially more applicants than places. Students attending these schools have many other college options.

The reason that more minority students don’t get college degrees has nothing to do with competitive admissions policies. The truth is that most minority students leave high school without the minimum credentials necessary to attend any four-year school, selective or not.

Freshmen must be “college ready” at virtually all four-year colleges. This means that students must be literate, must have a high school diploma, and must have taken certain minimum coursework. Overwhelmingly, minority students are not college ready. Dr. Jay Greene of the Manhattan Institute found that only 20 percent of black students and 16 percent of Hispanic students leave high school with these basic requirements.

Minority under-representation in college is the direct result of the public schools’ failure to prepare minority students. It is a failure that affirmative action does not remedy — college-ready minorities already attend college just as often as their white counterparts.

Affirmative action thus does not send more minority students to college. But it does redistribute college-bound minorities from less academically selective schools to more selective ones. Affirmative action supporters assume that this is helpful to preferred students: that moving a student from the University of Colorado to Cornell will enhance that student’s earning potential.

But economists Stacy Dale and Alan Krueger found that name-brand colleges are the modern equivalent of the Dutch tulip craze. Prices go up and up, but elite colleges offer no financial benefit that less selective schools do not.

Dale and Krueger compared students rejected by selective colleges with students who attended those schools. They discovered that when students’ entering credentials, such as high school grades and test scores, were the same, the rejected students made just as much money as those who attended “top tier” universities.

Students know something about themselves that admissions committees do not. If you think you are Cornell material, you are — even if Cornell doesn’t notice — and statistics show that you are just as likely as Cornell grads to succeed in the game of life. This means that preferences don’t raise minority incomes.

Racial preferences can’t send more minority students to college and don’t raise the incomes of those they move around, but they do reinforce a harmful myth: the myth that credentials, not skills, are the key to success. Students of all backgrounds suffer because elite schools perpetuate this myth.

Ivy league institutions maintain their status by rejecting far more applicants than they accept. To keep applications coming — and parents paying tuition — they practically claim to have bottled success. Anyone can rub elbows with the brilliant and powerful, they imply, and be set for life.

But studies show that skills, not name-brand diplomas, determine advancement in the real world. Harvard grads do well. But they do well because they are skilled and driven, not because they have Harvard degrees.

People hope that preferences will assist minority students whose tested proficiency in English and math lags behind their peers. But instead of addressing the critical skills gap, preferences reinforce the notion that skills aren’t important: that it matters who you know, not what you know. This untrue, self-serving message from the elite academy is among affirmative action’s heavy costs.