This November, voters in Colorado, Nebraska, and Arizona will have a chance to amend their states’ constitutions to eliminate preferential treatment based on race and gender in public education, employment, and contracting.

Here is the ballot language voters will consider in all three states:

“The state shall not discriminate against, or grant preferential treatment to, any individual or group on the basis of race, sex, color, ethnicity, or national origin in the operation of public employment, public education, or public contracting.”

Most observers believe the three initiatives will pass by wide margins, just as they did in California (1996), Washington State (1998), and Michigan (2006). Even the leading pro-racial and gender affirmative action group, the Coalition to Defend Affirmative Action, Integration, and Immigrant Rights and Fight for Equality by Any Means Necessary, admits that “the key to defeating the initiatives is to keep it off the ballot in the first place. That’s the only way were going to win.”

So, will John McCain, the Republican presidential nominee and Arizona’s senior senator vote for or against this initiative when he casts his ballot in Arizona on Election Day? It’s a fair question — one that needs a clear and unequivocal answer from him.

We know where Senator Obama stands on ending preferences — that position was staked out in 2006 when he campaigned against an identical voter-led effort in Michigan. As the former University of California regent behind all of the current and past anti-discrimination state initiatives, Ward Connerly, has pointed out, Mr. Obama cut a radio advertisement for the pro-preferences groups in which he claimed that minorities and women wouldn’t be able to get good educations or jobs if the Michigan proposal passed.

This is important for voters to remember. Despite his nuanced and eloquent rhetoric about the role of race and diversity in American life, Mr. Obama recently stated, “I still believe in affirmative action as a means of overcoming both historic and potentially current discrimination. But I think that it can’t be a quota system and it can’t be something that is simply applied without looking at the whole person … ” In other words, Mr. Obama wants it both ways: yes to race preferences, but they need to be packaged “individually.”

Mr. McCain’s position on race- and gender-based affirmative action appears not very different from that of Mr. Obama’s. Yes, like Mr. Obama, he’s against “quotas” and is for “equal opportunity.” But who isn’t?

In truth, this position tells us nothing meaningful — as any first-year law school student knows, the courts have been striking down “quotas” as unconstitutional for decades.

More telling is Mr. McCain’s opposition in 1998 to an amendment offered by Senator McConnell of Kentucky to a federal transportation bill that would have replaced race- and gender-contracting set-asides with ones designed to help all small businesses, regardless of the owner’s skin color or sex. His vote against the amendment back then was a mistake, but one he can learn from, and build upon.

Like far too many in the Republican Party today, Mr. McCain objects to any legislation or initiative that seeks to end racial preferences as “divisive,” fearing they only energize blacks and Hispanics to turnout at the polls in heavy numbers to vote Democratic, causing Republican candidates to suffer. That’s too bad because the election data from past Connerly-led civil rights initiatives shows this fear is completely misplaced.

The outcome of the Michigan Civil Rights Initiative in 2006 illustrates the point. Like their Democratic opponents, the Republican candidates in Michigan running for governor and the U.S. Senate opposed MCRI. Both Republicans lost by wide margins, while MCRI passed with 58% of the vote. Moreover, an analysis by Michigan-based political consultant, Chetly Zarko, revealed that MCRI did not drive up minority turnout.

It should not be lost on the McCain campaign that all three states to pass anti-preference initiatives have been solidly blue for the last four presidential elections. The states coming up this November — Arizona, Colorado, and Nebraska — voted Republican in 2000 and 2004. He needs to win all three to claim the White House.

Moreover, these three new initiatives give Mr. McCain an opportunity to propose a judicious policy for voters concerning the role of race and ethnicity in our nation’s public policies. Specifically, he should embrace the notion that racial and gender preferences be replaced with “class-based” or “need-based” ones, an idea that has floated around policy circles — on the right and the left — for decades.

Even Mr. Obama recognizes that race-neutral or “universal,” affirmative action programs are fairer and less polarizing than those that are defined by race. Nonetheless, Mr. Obama refuses to take this reasonable step and propose the elimination of governmental racial classifications and preferences altogether.

Mr. McCain should, however. He gains nothing by embracing the same flawed civil rights vision as Mr. Obama. Standing up for colorblind public policies and endorsing the Arizona initiative is not only the honorable and moral position, it will prove helpful in reaching working-class voters this fall.

It was an error for Mr. McCain to support race preferences in 1998. He shouldn’t make that mistake again.

Mr. Blum, a visiting fellow at the American Enterprise Institute, is the author of “The Unintended Consequences of Section 5 of the Voting Rights Act.”