In 2003 the U.S. Supreme Court, in a split decision, ruled that the University of Michigan’s undergraduate admissions systems amounted to an unconstitutional racial quota. But the court did allow state schools, if they wished, to continue using a more “holistic” system aimed at giving minorities the benefit of the doubt.

Dial forward three years. According to data once again wrested from the university under a Freedom of Information Act request, the Center for Equal Opportunity, based in Herndon, Va., found that a black applicant with a cumulative SAT score of 1240 and a 3.2 gradepoint average in high school has a 9-in-10 chance of being admitted to Michigan’s undergraduate program. For whites or Asians, the chances were 1-in-10.

In effect, nothing has changed in the People’s Republic of Ann Arbor. Which goes a long way to explain why Michigan voters are being asked to consider Proposal 2, the Michigan Civil Rights Initiative, which would flatly bar government from using “affirmative action programs that give preferential treatment to groups or individuals” based on race, ethnicity, gender, and other suspect factors.

Proposal 2 is the same as amendments to the California and Washington constitutions that were approved by wide margins. But a multimillion dollar ad campaign organized by labor, business, and political elites of both parties in Michigan is frantically throwing sand in the eyes of the electorate with charges that Proposal 2 would be the end of civilization as we know it.

The campaign may work. The Michigan Civil Rights Initiative has sunk to less than 50% approval in polls recently, down from 75%. “Michigan is a much tougher place, politically, than either California or Washington state,” says Ward Connerly, the California businessman who has backed all three measures. The chairwoman of the Michigan Civil Rights Initiative, Jennifer Gratz, who was the plaintiff in the original University of Michigan case, confesses her group has little money with which to respond.

But voters have plenty of reasons to see through the scare campaign. California and Washington are doing just fine in the wake of their bans on race preferences. Yes, minority enrollment at a few of the most selective state schools is down, but overall minority enrollment in the state system is up. Female contractors can no longer count on a big boost when bidding for government work, but female income continues to rise overall.

The anti-Prop 2 campaign suffers an even more crucial flaw: It has been simply unable to explain how more discrimination would lead to less discrimination. At a big rally against Prop 2 in Detroit 10 days ago, Jesse Jackson gave a particularly weird explanation of why he opposes a ban on preferences. Men of all skin colors play for the Detroit Tigers, he rightly noted, but no baseball fan would think to root for a St. Louis Cardinals player simply because of his skin color. “Diversity” leads to strength, he asserted.

But most people enjoy watching pro sports precisely because the players are picked solely on the basis of their amazing abilities. Competition is what makes people stronger. Do we not have a compelling interest in having our overall society perform as well as our professional sports teams?

I didn’t always see it this way. Back in the 1960s and 1970s, as a journalist working in New York, I wrote articles about what a great thing it would be if the City University of New York would open itself up to minorities through an “open enrollment” system. But 40 years later — and having seen CUNY nearly implode as a serious school as a result of open enrollment — I say it’s time to get back to first principles: Treat all individuals as equal before the law.

Mr. Bray is a columnist based in the Detroit area.