ONCE THERE WAS A rule of law that cases are not to be fought in the newspapers and that lawyers who go public outside the courtroom are frowned on as self-promoters.

But, after the U.S. Supreme Court put its imprimatur on lawyer advertising two years ago, and as the public's fancy for news and gossip about the legal profession kept growing, the rules began changing.

As a result the profession has slowly taken on a peculiar new dimension: public relations specialists for lawyers.

It seems an unholy alliance -- the slick image maker whispering in the ear of the bar. But, some lawyers say, when they are dragged before the public, they need advice about what to say and how to say it.

"I don't think it's right. It's not the way I was brought up," said one Washington lawyer whose firm has employed a public relations man.

Lately, he said, it seems some cases are tried "before the court of public opinion. [And] if you're going to try a case in that court, you better learn the rules."

This lawyer is learning the rules from Stephan Lesher, a veteran reporter who quit journalism two years ago to team up with Gerald Rafshoon, the president's public relations man. A coupleof months ago, Lesher split with Rafshoon and started a public relations firm. His clients, for the most part, are lawyers.

Now that he has switched sides, Lesher is drawing on his reporter's experience for all it is worth. Not only does Lesher advise lawyers about what kind of legal action makes news, when to say "no comment," when to talk and to whom, he also said he helps lawyers write in plain -- and quotable -- English as opposed to legal "hogwash."

When reporters need a news "peg" for a story, Lesher tries to get them one. Once, when a client wanted some publicity for its side of a dispute before a federal regulatory agency, Lesher advised the client to file a formal response with the agency, including challenges to statements already made to the press. The client took the advice, Lesher said, and Lesher helped him draft the complaint. Sure enough, the client received the press coverage he wanted.

"It's like show business. Always leave them laughing. Give them what they want," Lesher said during an interview.

In that case, Lesher said, the objective was to influence the public about the corporation and, ultimately, its product. Other times, however, the publicity is aimed at stockholders, such as when a merger battle is on, or at legislators when laws are being drafted. At no time are the public relations consultants and the lawyers trying to influence judges or juries, Lesher said.

One might ask if this practice didn't amount to abuse or at least distasteful manipulation of the system. Not so, Lesher said. "The system is ultimately political," he said. "The system is to be used. That's what it's for."

Perhaps hiring a public relations expert to teach a lawyer how to use the media is no different from paying an orthopedist to tell a malpractice lawyer how to make the most of bones to win a case. And any reporter knows that a canned response from a public relations consultant sometimes is better than a plain "no comment" from a grouchy lawyer. And who's to complain when a public relations consultant telephones a reporter and plants a story idea?

Plenty of lawyers have made the art of publicity an element of their practice. A subtle public relations consultant simply does the job for the unschooled -- for a price.

"How do you get your point across? You do it in a way that's going to attract the media. You do it in a perfectly correct, ethical way through perfectly open channels," Lesher said.

As long as public relations efforts stick to the facts, they fit within the bounds of the American Bar Association's code of ethics for lawyers, said Bays Shoaf at the ABA's National Center for Professional responsibility.

"I just regret that lawyers are coming to the point where they think they need to get into that kind of thing," Shoaf said.

With the birth of lawyer advertising, public relations firms took on the business of producing "institutional advertisements" for lawyers -- image promotion for the profession. Their clients, however, are the organized bars.

Shoaf and others seemed puzzled that individual firms and lawyers think they need the kind of personal service and advice that public relations firms offer.

"I would think most lawyers in most firms are big-headed enough" to take care of themselves, Shoaf said.

There have been occasions in which big law firms have turned to public relations consultants when the firm's image has been publicly wounded. The National Law Journal has reported that Washington's Hogan & Hartson used the New York public relations firm of Doremus & Co. to help circulate a press release and rebuttal to a court-ordered report about the firm's relationship with fugitive financier Robert Vesco. Vesco controlled a corporation that was a client of Hogan & Hartson.

And when a partner at New York's Donovan, Leisure, Newton & Irvine was forced to resign after it was disclosed that he lied in federal court, the firm turned to a public relations man to help draft answers to press queries, the Journal reported.

New York's Howard Rubenstein, a lawyer who now is a public relations consultant, says such actions are not a trend but rather a temporary solution "from time to time when a law firm has a knotty public relations problem."

But unless the public cools its fascination with law, and unless reporters lose their interest, which is as unlikely as it is undesirable -- publicity for lawyers is here to stay and the lawyers' public relations consultant a fact of life.

OBITER: Robert A. Anthony has resigned as chairman of the Administrative Conference of the United States to practice law with Sellers, Conner & Cuneo in Washington. The conference, an independent government agency, makes recommendations to the federal regulatory agencies, Congress and the president on improvements in federal administrative procedures . . . Robert M. Smith, 38, a former New York Times investigative reporter in Washington now practicing law in California, is expected to be named director of the Office of Public Information at the Justice Department and special assistant to Attorney General Benjamin R. Civiletti. Smith, who earned his degree at Harvard College, Columbia University, and Yale Law School will take over for Terrence B. Adamson, who plans to teach at the Institute of Politics at the Kennedy School of Government at Harvard University . . . Frederick Baron, a special assistant to former Attorney General Griffin B. Bell and a specialist in intelligence matters, has taken a job as an assistant prosecutor in the U.S. Attorney's office here . . . John Clifford, formerly a senior supervisory attorney in the D.C. Corporation Counsel's office has moved to Tepper and Edmundson in Washington.