Harvard Law School Dean James Vorenburg, in an unprecedented open letter to 28,000 alumni last week, has responded to what he called widespread concern that a "war-like atmosphere" threatens intellectual standards at the nation's most influential law school.

Vorenburg's letter officially acknowledged that bitter ideological fighting between left-wing and right-wing faculty in recent years has slowed hiring and made it more difficult to retain top-level teachers at Harvard -- a school whose graduates fill the upper ranks of business and the legal profession as well as the faculties of other top-ranking law schools.

Harvard, long considered the pinnacle of legal scholarship, has not been able to hire a full professor away from another law school since 1981, usually because the faculty cannot agree on a candidate.

"The divisions are real and sometimes damaging," Vorenburg conceded in the three-page, single-spaced letter dated Dec. 10. But the school is also in a period of "great achievement," he said, adding that news media accounts have exaggerated the tension.

Vorenburg's message on the hiring deadlock was unusually blunt: Either the 50-member tenured faculty, which must approve new hiring and promotion by a two-thirds vote, will focus on scholarship -- not politics -- or he would do the hiring himself.

"I am also prepared to act to prevent any deadlock in making . . . tenure and tenure-track appointments," Vorenburg said, adding that he had the support of university president Derek Bok to bypass the faculty.

"I do not expect this process will always be easy or peaceful," he said, "but since nothing is more important to the continued strength of the school, I am determined that we will be successful."

The trouble began, according to most observers, when a small group of New Left radicals arrived on campus in the 1970s and began to challenge the most cherished assumptions of legal studies, including the assumption that there is something called "law" and that it is worth studying in the traditional case-study methods pioneered at Harvard and popularized in the movie "The Paper Chase."

The radicals founded a movement called Critical Legal Studies. CLS, an outgrowth of the Legal Realism movement in the 1920s and '30s, has hundreds of adherents, but Harvard is the only law school with a significant cluster -- perhaps five to seven -- of tenured professors who are members.

According to one of CLS' founders, Harvard professor Duncan Kennedy, it is in part "really a rag-tag band of leftover '60s people." It is a movement that views law not as a body of politically neutral principles, but rather as something the wealthy and powerful use to justify and consolidate their power.

For CLS followers, sometimes called "criticalists" or "critters," law is simply politics by another name. It can be, and is, used by lawyers, judges and politicians to justify any outcome or, in the language of its exponents, to "reproduce illegitimate hierarchies."

The CLS movement, Kennedy said, believes that "the existing rules in force, the law as we have chosen to make it through our various lawmaking institutions, is profoundly implicated in distributional, social injustice in our society. The system by which the rich and powerful, white and male, stay rich and powerful, generation after generation, has a very strong legal component."

To the more traditional law professors who have devoted their careers to expounding legal doctrine, the CLS views are heresy, in addition to being wrong.

The leftists' style also rankles traditionalists. Kennedy, for example, has proposed, among other things, a lottery for student admission and paying janitors the same salaries as professors. CLS followers were also blamed for instigating a two-day student rebellion in 1983 against being graded on class participation. The revolt included a sit-in in Vorenburg's office.

One leading faculty conservative, Robert Clark, summarized the struggle last May at a symposium in New York. "Some members of the CLS movement have . . . denigrated the work of older members of the faculty. They have engaged in . . . a ritual slaying of the elders," which has produced resentment.

A second reason for the prolonged, bitter conflict is that CLS, by attracting the votes of younger liberals, has "acquired power," Clark said. "They always vote in a bloc on appointments matters," he argued.

Kennedy, at the same panel discussion, acknowledged that "people's feelings get hurt. When people's feelings get hurt, the left accuses the right of purging assistant professors for political reasons. The right accuses the left of voting only for its friends."

Traditionalists argue that, name-calling and politics aside, the leftists have disparaged intellectual study. They point to a proposal by Kennedy to have a "no-hassle pass" in which unprepared students called on in class could decline to answer and not be subjected to ridicule.

Professor Paul Bator, a former deputy solicitor general who is leaving after 26 years at Harvard to go to University of Chicago law school, said "the Harvard Law School is the only educational institution I know where it is considered a symptom of right-wing extremism to be in favor of rigorous standards of scholarly excellence."

Bator said "serious and productive non-left scholars do not want to be at an institution devoted to guerrilla warfare."

Vorenburg, trying to maintain some neutrality in the battle, said in an interview that he did not think "there is guerrilla warfare going on here," and that the political friction has not "led to anyone declining a job."

There have been two exceptionally nasty fights in recent years over appointments, according to faculty sources. The left blocked one candidate about three years ago and the right temporarily vetoed elevation of an assistant professor last year.

While some conservatives, some of whom reportedly are considering leaving, have been vocal in recent months, the usually rambunctious left has been uncharacteristically quiet.

One faculty member said the left is silent now because "they the conservatives have hostages" -- a group of about 10 assistant professors, mostly left-leaning, who will be considered for tenure within the next two years. Tenure at the school traditionally has been given to almost anyone eligible, but there is an unusually large number up now, and a fear -- or hope -- that not all will make it.

"A lot of people coming up are lefties," a source said. "If they are not promoted there will be allegations of a vendetta." On the other hand, he said, conservatives oppose several of them and, if they are promoted, the right will say "it is because of the constant kowtowing to the critical legal studies."

Vorenburg, in his letter, said, "Life here would often be better if we were a more easy-going group," but the school is still a "congenial place to work."

In an interview, he said "this picture of a cantankerous, unpleasant place isn't so. The thing that is so discouraging sometimes is that I think this is a productive time here," he said, listing a number of new programs. "Yet all of that somehow tends to get lost because conflict -- with a capital 'C' -- is what captures attention."