In the courts, and in the court of public opinion, the opponents of affirmative action are winning.

They have won a ballot initiative in California banning the use of race and sex in college admissions, contracting and public employment. They have gained enough signatures on petitions to place a similar initiative on the ballot in the state of Washington.In Texas, they have prevailed in court suits to end preferences for minorities and women in college admissions, and to force the state government and the Clinton administration to scale back affirmative action efforts in the awarding of contracts.

In Piscataway, N.J., their string of successes has scared civil rights groups into seeking an out-of-court settlement of a teacher's challenge to her school district's affirmative action plan.

But with victories come doubts, and as the opponents of affirmative action see what they have wrought, some of them have begun to recoil in horror.

Fresh evidence of the fruits of their opposition was unveiled last week when the University of California at Berkeley and the University of California at Los Angeles disclosed the racial and ethnic makeup of their incoming classes. Berkeley reported a 57 percent drop in the number of black applicants and a 40 percent decline in the number of Hispanic high school seniors who had been accepted for admission. For UCLA the decline was 43 percent for African-American students and 33 percent for Hispanic Americans.

"Perhaps the most important lesson I've learned is that there are no airtight, completely coherent, unassailable and holistic answers on the question of affirmative action that are not only theoretically perfect, but instrumentally practical," said John Bunzel, who, as president of San Jose State University, had written stinging critiques of affirmative action but is now more disposed toward it. "Any intelligent person who wrestles with it is going to be vulnerable and subject to the twists and turns of unintended consequences."

Even before the latest statistics emerged from California's elite public universities, some conservatives seemed to be getting more prone to hand-wringing. For example, Nathan Glazer, the noted Harvard sociologist, has even given up his opposition to affirmative action in some cases. Two weeks ago, Glazer wrote in The New Republic that ending affirmative action would visit so much damage on the aspirations and advancement of blacks that opponents of granting preferences to qualified black college applicants should rethink their position.

"I believe the main reasons we have to continue racial preferences for blacks are, first, because this country has a special obligation to blacks that has not been fully discharged," he wrote, "and, second, because strict application of the principle of qualification would send a message of despair to many blacks, a message that the nation is indifferent to their difficulties and problems."

For Glazer, it is a clear case of modifying views when principles meet reality. "It's the consequences," he said in an interview from his home in Cambridge, Mass. "It's one thing to fight for a principle, which is a very good principle, especially if you don't expect it to win. Then, as you come close, the consequences become a little larger."

Glazer and Bunzel are not alone. In recent years they have been joined by Glen C. Loury, a Boston University economics professor and former aide in the Reagan administration, and James Q. Wilson, a sociologist at UCLA. In some cases they have maintained a strong antagonism toward granting preferences in government contracting or in employment. But college admissions seem to have warranted a second look.

Such sentiments, of course, remain apostasy among many opponents of affirmative action. These opponents argue that whatever the numbers coming out of California show (including how deeply preferences were ingrained in admissions policies), the adjustment now being recorded represents only a short-term pain that blacks and Hispanics must bear.

Their argument remains that affirmative action is like a placebo that only masks the need for a real cure - namely, an adjustment by individual schools and families to a no-preference world, in which harder striving would produce real equality. This, they say, comes only with time.

"We have a lot more confidence than the Nat Glazers of the world that with good education you will end up with parity in academic performance," said Abigail Thernstrom, co-author with her husband, Stephan, of "America in Black and White: One Nation, Indivisible" (Simon & Schuster, 1997). "There is a kind of throw-in-the-towel pessimism that I think is behind a lot of support for preferences that we don't sign on to."

For some, like Loury, the problem with such arguments is that the only alternative proposed by the critics of affirmative action seems to boil down to simply exhorting blacks and Hispanics to work harder.

With figures showing that Berkeley turned away 800 black applicants who had 4.0 grade point averages and scored at least 1,200 on the Scholastic Aptitude Test, Loury said it is clear that many African-American students are already working very hard. Yet their efforts and the goal of a diverse student body - an idea that the critics of affirmative action say they value - apparently aren't enough.

"Is the sole measure of merit or worth the performance on these tests?" Loury asked. "Is there no value at all to racial diversity?"

Only a small group of conservatives and political centrists, of course, make up this network of affirmative action foes who are having second thoughts. But, then, the movers and shakers against affirmative action - the lawyers who file the suits, the lobbyists who buttonhole legislators, the advocates who gather signatures on petitions for ballot initiatives and the far right foundations that fund them all - also form only a tiny group.

And some former opponents - Glazer, for example - have a special stature because they were at one point the movement's intellectual trailblazers, and their words have the power to convert. Gerald Reynolds, president of the Center for New Black Leadership, a Washington-based organization that is a staunch foe of affirmative action, recalled reading Glazer's critiques of affirmative action while a student at York College in New York.

"Nathan Glazer's arguments persuaded me that racial preferences are extremely harmful to the beneficiaries," he said.

More significantly, the former opponents reflect the ambivalence of a much larger and more important institution: the Republican Party. Republican leaders like House Speaker Newt Gingrich have been vocal critics of affirmative action. Yet for some reason - concern about the fallout, a desire to attract black or Hispanic voters - when it comes to killing it off, the Republicans have not been able to pull the trigger. It is one reason that backers of affirmative action have been able to beat back attempts in 13 state legislatures to ban the practice.

All of this drives those who have held firm against affirmative action to distraction.

"The arguments that Glazer and Loury made in the past against preferences are some of the strongest arguments," Reynolds said. "The only thing I can say to those who would embrace a policy that they already rejected in theory is if they don't have the stomach for it, they should get out of the debate."