TWENTY-FIVE years ago, a group of skeptical liberals founded a magazine called The Public Interest with the goal of fighting ideological rigidity and "prefabricated interpretations of social realities." Though they didn't realize it when they started their magazine back in 1965, these heterodox liberals were creating not only a journal but also a new political movement. They were dubbed "neo-conservatives" by the late Michael Harrington, one of their most articulate critics, and the name stuck.

The very best things about neo-conservatives were their refusal to be guided by shibboleths and their skepticism of ideologues. But over the years, neo-conservatism has developed a problem -- more and more it has become just plain conservatism. Increasingly, there is little that is "neo" about the neo-conservatives, partly because they have given in to those "prefabricated interpretations" of which they were once so skeptical.

The shift in the neo-conservative worldview can be traced to a sharp change in the movement's priorities. Initially a group of intellectuals mainly concerned with domestic policy, the neo-cons came to be identified more and more with foreign policy, notably a hard-line approach to the Soviet Union. This, in turn, led the neo-cons to the right on a host of other issues. What got lost in this transition was the original spirit of The Public Interest, which was sprightly, independent and deeply skeptical of all ideologies -- including conservatism.

That spirit is still alive, but with a few exceptions the people keeping it alive are mainly liberals. Among them are some of The Public Interest's founders -- notably Sen. Daniel Patrick Moynihan (D-N.Y.) and social theorist Daniel Bell -- who chose not to join the right.

The early neo-conservatives were attractive because of their devotion to evidence and their insistence that wisdom carried no labels. In their earliest days, The Public Interest crowd argued, with the conservatives, that social problems would remain insoluble unless policy-makers paid attention to the importance of individual "virtue," a word the future neo-cons revived from ancient and medieval philosophy. When many opinion leaders were giving up on "bourgeois values," the neo-conservatives suggested that bourgeois institutions like the two-parent family worked better than most of the available alternatives.

But in paying attention to individual virtue, the early neo-cons did not simply condemn the poor to their fate. Neo-conservatives applied much energy to trying to link income maintenance programs with work incentives. One result of their efforts was Richard Nixon's Family Assistance Plan, largely crafted by that professional reformer, Daniel Patrick Moynihan.

Today, the neo-conservatives can legitimately boast that they changed the way both liberals and conservatives approach social policy. By preaching that all kinds of government programs had "unintended consequences," they made liberals uneasy -- many would say timid -- about proposing too many of them. By insisting that government had a responsibility to put a floor beneath society's poorest, the neo-cons converted many mainstream conservatives, who had once rejected the welfare state wholesale, to at least a grudging acceptance of many of its features. It would be politically impossible for a conservative like Jack Kemp to be as bold as he is in discussing the problems of poverty if the neo-cons had not done their missionary work.

If there was a single animating idea behind The Public Interest at its inception, it was "the end of ideology," which was the title of one of Bell's most influential works, published in 1960. What Bell said then seems remarkably on point in the age of Vaclav Havel:

"For the radical intelligentsia, the old ideologies have lost their 'truth' and their power to persuade," Bell wrote. "Few serious minds believe any longer that one can set down 'blueprints' and through 'social engineering' bring about a new utopia of social harmony."

Founders Bell and Irving Kristol echoed these sentiments in their introductory editorial in The Public Interest debut issue five years later. The worst obstacle to clear thinking, they said, was "a prior commitment to ideology, whether it be liberal, conservative or radical."

"For it is the nature of ideology to preconceive reality," they went on, "and it is exactly such preconceptions that are the worst hindrances to knowing-what-one-is-talking-about."

The original Public Interest had no lack of faith in social programming. Rather, it had an excessive confidence in social policy experts. Early on, this gave the neo-cons an unfortunate anti-democratic tinge.

The lead article in that first issue (by Moynihan) spoke with some confidence about "The Professionalization of Reform." In an argument that in some ways foreshadowed Francis Fukuyama's recent comments about the torments of "the end of history," Moynihan argued that the professionalization of reform would lead to a decline in "the moral exhilaration of public affairs at the domestic level." But that was a small price to pay, given that American society had it within its reach to "put an end to the 'animal miseries' and stupid controversies that afflict most people."

If history did not turn out quite that well, the magazine itself, in its early years at least, held true to its promise to eschew ideology. The first issue included articles by the devoutly conservative sociologist Robert A. Nisbet and the socialist-leaning economist Robert L. Heilbroner. Nathan Glazer wrote of the successes of the Freedom Schools and the Community Centers in the Deep South and suggested that the federal government help finance black-run organizations. Jacques Barzun offered suggestions on how government could best help finance the arts.

In quieter times, The Public Interest might have continued along these lines, and most of the heretical liberals and social democrats who were drawn to the magazine might have remained liberals and social democrats. But in the late 1960s and 1970s, controversy intervened. In the ensuing polarization, most of The Public Interest crowd moved right. What was born was the harsher brand of criticism that is now widely associated with neo-conservatism.

The neo-cons were especially upset by the student left's attacks on the university in the '60s. After all, many neo-cons are the children and grandchildren of immigrants -- intellectuals who revered the university both as the source of their own upward mobility and as an arena of freedom.

Nixon's detente policies pushed the neo-conservatives farther right still. When the Great Kitchen Debater himself became willing to do business with the Soviets, many a neo-con had to look to the outer reaches of the conservative spectrum to find someone who agreed with their foreign policy views. (His name, it turned out, was Ronald Reagan.)

And when the focus of the civil rights movement shifted from integration to affirmative action, more neo-conservatives were pushed farther from the liberal cause. To them, affirmative action meant "quotas"; many of the neo-conservatives are Jewish and their memories of quotas were decidedly negative. When some on the left turned against Israel, their disaffection was complete.

The merits of these various choices can be debated, but the results were clear: Neo-conservatives began to embrace the very ideological approach to politics that they had once condemned.

Thus Mark Lilla, a former editor of The Public Interest, acknowledged 10 years after the magazine's founding that neo-conservatism was increasingly inclined toward "a new, more aggressive line of argument" which held that "whether well-intentioned or not, the attempt to expand government simultaneously in many social spheres has been a counter-productive mistake." That, of course, is Old Right thinking, and it raises the question of what an ideological neo-conservatism has to tell us now that is different from what mainstream conservatism has to say.

Some neo-conservatives, including Kristol, their most effective impresario, welcomed the embrace of full-hearted conservatism. Kristol argued that intellectual honesty demanded that the neo-conservatives give up on the romantic socialism of their youth and begin using the C-word -- capitalism -- with real respect.

To the dismay of some of the older conservatives -- who, in reaction to the neo-cons, dubbed themselves paleo-conservatives -- the neo-cons did very well in winning appointments and acclaim during the Reagan years. Some of the most prominent figures in the Reagan administration -- Jeane Kirkpatrick, Elliott Abrams and William Bennett -- were drawn from the neo-conservative family.

But with real power came increasing rigidity, and ever greater hostility to those who made themselves conservatism's adversaries.

The newly dogmatic version of neo-conservatism takes many forms. Many in the ranks, for example, still speak as if the New Left were at the gates, burning down university administration buildings and cheering for the Viet Cong. In a recent letter to supporters of the Committee for the Free World, the organization's president, Midge Decter, spoke for many in the movement in condemning leftists who regularly joined the "chorus of disaffection toward their own country and its political and social institutions."

The problem with this view is that the "chorus of disaffection" isn't very loud in 1990. Sure, there are still some folks around who think that the United States is incapable of doing anything good in the world. But there are not that many of them and neo-conservatives so far seem unable to savor the changed mood.

Whatever his failures at home, Mikhail S. Gorbachev is forcing much new thinking in the United States, among neo-cons no less than among others. Neo-conservatives are engaged in a vigorous debate over how to deal with Gorbachev and whether he is "for real." When two of the leading nabobs of neo-conservatism, Kristol and Norman Podhoretz, can engage in a vigorous debate over the proper American response to Lithuania -- as they did at a recent Washington meeting -- that suggests that the neo-cons can no longer count on those once-condemned "prefabricated interpretations of social realities" that had come to guide their way.

Neo-conservative uncertainty over foreign policy may also pave the way for a new engagement with domestic issues, and there are signs that the neo-conservatives are joining what Moynihan has called "the return to social policy." In recent years, The Public Interest has been opening its pages to heretics on the left like Christopher Jencks and Steven Kelman. The neo-cons are once again expending a good deal of energy trying to figure out what the government might do to lift the underclass and to provide housing for the needy.

But the heretical imperative is having its greatest impact on liberals. The new liberal magazine, The American Prospect, was widely miscast as simply a replay of the old liberalism. In fact, its first issue included a series of heterodox articles that could easily have found a home in the early Public Interest -- Jencks on welfare mothers who are forced to work illegally and William Julius Wilson on how non-racial approaches to social programs could do the most to help the black poor.

Slightly farther left, Dissent magazine, a stronghold of democratic socialist thinking, is becoming the center of a vigorous debate on how socialists are coming to terms with markets. And magazines like The New Republic and The Washington Monthly continue to challenge orthodoxies while maintaining faith in the possibilities of government.

Those neo-conservatives who have actually become full-fledged conservatives will not enjoy seeing liberals steal their brightest clothes. But if the neo-cons remember their past, they should welcome a reopening of the social policy debate along less rigid lines. The lesson The Public Interest tried to teach 25 years ago is still valid: Heresy in pursuit of good public policy is no vice.

E.J. Dionne Jr. is a Washington Post reporter.