When Nebraska voters on Tuesday barred the consideration of race in public college admissions decisions, and other government operations, there wasn't much ambiguity about the outcome. Fifty-eight percent of voters backed the ban. That's the same percentage of voters in Michigan who backed a ban in 2006. That's the same percentage of voters who backed a ban in Washington State in 1998. The first statewide referendum on such a ban -- in California in 1996 -- was comparatively close. Only 55 percent of voters approved it.

All of this is to say that when voters have a chance to shoot down the consideration of race in college admissions, they have taken that option with gusto every single time -- except for Tuesday in Colorado. There, a similar proposed ban was on the ballot. While some votes still haven't been counted, the measure was narrowly behind late Wednesday, with 50 percent voting no and 49 percent yes. Enough provisional ballots exist that no one is calling the outcome.

Even if the measure somehow pulls out a victory, the Colorado experience appears to demonstrate that it is possible to defeat a proposed ban at the ballot box. Until now, defenders of affirmative action have feared that once an item is on the ballot, it was almost inevitably a winner.

"I am surprised. I expected that this initiative would pass easily," said Richard D. Kahlenberg, a senior fellow at the Century Foundation, author of The Remedy: Class, Race, and Affirmative Action. "There are states that are darker blue than Colorado -- Michigan, Washington, California -- that passed these sorts of initiatives."

So what happened in Colorado? And what happens next?

For now, vote counting continues. If the final outcome is within 0.5 percent (not the case now, but certainly a possibility), a recount will take place. The why is more difficult to determine.

Defenders of affirmative action point to a tough strategy in which they didn't just talk about the benefits of diversity, but directly attacked the sponsors of the ban and challenged just about everything about it -- from its name to its purpose. Proponents of banning the use of race say that this campaign was unfair and confusing to voters. Both sides admit that one factor may be that many Colorado voters are fed up with voter initiatives -- which were plentiful this year. When voters get frustrated, they are more likely to vote no than yes.

Melissa Hart, an associate professor of law at the University of Colorado at Boulder and one of the chief organizers of the campaign to defend affirmative action, said she was "incredibly proud that the organization has come this close" to an outright win. She said the success was due to a variety of efforts, including traditional door-to-door canvassing.

But even a quick glance at the No on 46 Web site shows a very different, and more aggressive, strategy than that used in other states. Some of the states that first faced these referendums responded with arguably highbrow approaches -- speeches by prominent educators, research studies and so forth. In Michigan, defenders of affirmative action had high hopes for advertising that emphasized the role of affirmative action in helping women, not just members of minority groups.These approaches appear to have been largely ignored by voters.

On the No on 46 Web site, there is information about how the Ku Klux Klan backs the movement to bar affirmative action. There are ads attacking the pay given to Ward Connerly, leader of the national movement to eliminate the use of preferences, and a critique of the way the measures in Colorado and elsewhere have "civil rights" in their names. "When voters see the truth about the referendum, they don't like what they see," said Hart. "People hear that this is a civil rights measure and think it's about ending discrimination and when you tell people that it's about ending affirmative action, they are shocked," she said.

The emphasis of the campaign, she added, was "educating voters so they wouldn't be fooled."

Jessica Cory, executive director of the Colorado Civil Rights Initiative, which backed the proposed ban, agreed that this approach had an impact. "It was a relentless, ugly campaign," she said. The Klan has nothing to do with the Colorado measure, she said, and attacks on Connerly are "stealing the identity of a black civil rights hero." Cory said that she thinks the measure would have passed comfortably but for the "last minute vicious attacks" of those defending affirmative action.

Jennifer Gratz, who is one of the leaders of the American Civil Rights Initiative, the group through which Connerly promotes his campaign, said that those who oppose the consideration of race in admissions decisions wouldn't be deterred by the vote in Colorado. "America is on a path to end race preferences," she said, and more states will see votes. "This is a marathon, not a sprint."