WHAT IS LEFT to be said about the FBI's relentless pursuit of Martin Luther King Jr. during the 1960s?

Nearly everyone knows that the bureau wiretapped and bugged King for years, tried to tar him as a Communist, sought to disrupt his personal life, and even made a hamhanded attempt to force his resignation from the Southern Christian Leadership Conference and replace him with someone more to the FBI's liking. It was clear long ago, even while both men were still alive, that through some peculiar chemistry, Martin Luther King Jr. brought out the very worst in J. Edgar Hoover and became the object of the FBI director's obsessive hatred, causing Hoover to make some of the worst mistakes of his long and checkered career.

Now comes David J. Garrow, who teaches at the University of North Carolina, with a new, important, and profoundly inquiring analysis of the bureau's war against King. The format is academic and at times irritating, but Garrow's book nonetheless helps us understand more about what went haywire in American society in the '60s.

Relying heavily on personal interviews and on documents obtained under the Freedom of Information Act, Garrow identifies and explains three separate phases in the FBI's investigation of King. The study of "Communist influence" over the "Negro Movement," the effort to "neutralize" or even "destroy" King personally and the search for political intelligence about the civil rights and antiwar movements. He rejects some of the standard explanations for the bureau's behavior, including the interpretation that Hoover simply felt a need to fight back viciously at any prominent person who criticized him or his bureau, as King had done.

The first phase of the King investigation, Garrow argues was motivated by a genuine (if largely unsubstantiated) fear of Communist infiltration of the civil rights struggle; the second, by the disgust of both "the puritans" and "the voyeurs" in the FBI and elsewhere in government over King's personal behavior; and the third, by anxiety over the political and cultural threat that King symbolized for the American majority.

Along the way, Garrow provides a dramatic and sensitive portrait of King, warts and all--one which, ironically, might not have been possible without resort to the results of the FBI's electronic surveillance of the civil rights leader. He also reveals, apparently for the first time, details of an FBI undercover operation, code-named "Solo," which for many years provided the Bureau with rich detail on the internal operations of the American Communist Party and its financial ties to the Soviet Union. It was "Solo" that brought the FBI's attention to former Communist Stanley Levison, one of King's closest friends and advisers.

But this book also reminds us that the 1960s were a time of red-baiting for the United States almost as serious as the periods just before World War I and just after World War II. Here is the FBI proceeding on the assumption that "once a Communist, always a Communist." (In one instance, that would be laughable were it not so deplorable, an FBI field office reports that it has found nothing subversive about one of King's associates--only to be rebuked by headquarters for not establishing that he was "anti-Communist"). Here is the CIA interpreting the growing opposition within the civil rights movement to the American involvement in Vietnam as the work of "Peking-line Communists." Here are key officials of the Justice Department and the White House during Democratic administrations, accepting the FBI's careless labelling of American citizens without so much as seeking proof or explanation.

Garrow's work reinforces earlier evidence about the Bureau's abuses, and it is especially good on the subject of "the unfortunate William Sullivan." The FBI official who would in retirement portray himself as the foremost defender of civil liberties in the bureau's ranks, but who turns out to have left a paper trail implicating him in the most heinous invasions of King's privacy.

Yet what is still remarkable after all these years is the list of other names--outside the FBI--that are implicated in the hounding of King. If Sullivan despised King on the basis of "puritan" instincts, those same instincts badly clouded the judgment of Robert Kennedy; if Hoover was the archetypal "voyeur" titillated by his tapes and transcripts of King, he scarcely outdid Lyndon B. Johnson. And then there is the parade of Johnson aides, many of them still active in public life, who among others, Garrow thinks, used the investigation of King as the cover for their blatant political abuse of the FBI during the Democratic National Convention of 1964 in Atlantic City.

Because this story necessarily ends with the assassination of King in Memphis in April 1968--in which the FBI is not implicated--the subsequent abuse of the bureau and the rest of the American intelligence apparatus by the Nixon administration scarcely comes up here; but it is precisely because the later Republican exploits are so well known that it is useful to recall the earlier Democratic ones.

It is also useful to remember that the horrors detailed in this book could be repeated tomorrow, if a few existing guidelines were repealed and if the bureau were put back into the hands of someone so inclined. To this day, no legal charter has been enacted telling the FBI what it can and cannot do. Although the current FBI director William Webster, and his predecessor Clarence Kelley, said they would welcome such a charter and although a reasonable (albeit imperfect) one was once drafted, its chances of adoption are slim indeed because the talk now is of the need to free the various intelligence agencies from unreasonable restraints.

Similarly, the talk now is of the need to tighten up the Freedom of Information Act, so as not to impede these agencies from doing their necessary work.

If that effort succeeds, one big difference will be that if and when the abuses occur again, it will be far harder to document them the way David Garrow has done. Perhaps it will be more comfortable not to know what outrages could be committed in the name of internal security and the public good. $90By SANFORD J. UNGAR; SANFORD J. UNGAR, host of "All Things Considered" on National Public Radio, is the author of FBI: An Uncensored Look Behind the Walls.