A WHISTLEBLOWER IS A public servant who, at risk of his job and future, discloses the questionable or illegal practices of his superiors.

A mercenary snitch is a government worker who willingly assists his superiors in such practices until, having reached the safety of retirement, he sells his secrets to a publisher.

Judging from Breaking Cover, Warren L. (Bill) Gulley would appear to be a mercenary snitch.

Gulley spent most of his adult life as a noncom in the Marine Corps. Strictly by the luck of having a buddy in the White House, he was brought into that establishment in 1966 as part of the Military Office and wound up running it for most of the next 11 years.

Gulley's tale is spun around a secret, multimillion-dollar fund that was established for the Military Office in 1957 to pay for digging holes in which the president could hide from nuclear attack. After the military had dug more than 75 of these caves at various spots around the country, the administrators of the fund began channeling the money into other things, some of them illegal. By the time Gulley reached the White House in the Johnson administration, the fund was being systematically looted.

Gulley says LBJ spent some of it to update his Texas ranch; Nixon built himself such luxuries as a half-million dollar swimming pool at Camp David; Ford used the fund to rent villas for his staff in Vail; and Carter used it for such things as paying "for plans for a presidential support compound on Billy Carter's land." (Gulley claims that when the president's mother found out about these plans she said to Billy, "Get all you can, honey. If they'll give you a hundred thousand, take a hundred thousand. Get all you can, because you'll never get another chance like this.")

For various reasons, I suppose this book will get some passing attention. Populists may enjoy the irritation that comes with learning that the White House had a package of crab meat flown up from Miami for Haldeman and Ehrlichman on their last weekend at Camp David before their resignations -- at a cost to the taxpayer of $500 a pound. Skeptics who were already convinced that the "burden" of the presidency is highly overrated may be mildly gratified to learn that Nixon sat around for hours trying to decide whether or not to salute when the national anthem is played at baseball games (he decided to salute), and that Haldeman engrosed himself in such decisions as what size (small bar) and brand (Dial, not Dove, for men guests) of soap to supply at Camp David.

Historians will want to weight Gulley's confirmation that Lyndon Johnson bugged the Oval Office and cabinet room much more elaborately than Nixon did. They will also want to consider Gulley's theory that Deep Throat was Scott Armstrong, then an investigator for the Senate Watergate Committee and today a reporter for The Washington Post, best known as coauthor of The Brethren.

Gossips will relish Nixon's alleged description of Nancy Reagan's dominance of Ronnie. Chronic worriers will welcome Gulley's warning that the White House security system is worthless and that the Secret Service is "the worst, most inefficient, badly run, highly political outfit in the United States government." Collectors of the seemingly endless scatalogical stories about LBJ will enjoy one Gulley tells about Johnson urinating on a Secret Service agent's shoes.

But little spots of greenery are uncommon. Most of the book is a wasteland of bland opinion and trivial anecdotes. It is, in fact, troubling that a person could emerge with nothing more weighty than this to tell after spending 11 years running an office that coauthor Mary Ellen Reese claims is so vital that, without it, "the Presidency literally could not function." (Quite an exaggeration.)

I'm also bothered by the question of how far to trust Gulley. He sounds like a sharpy. Though he now ridicules much that they did, he says he felt "adulation" for the four presidents he served and questioned nothing about their conduct. "In the White House," he says, "you never worry about the law, it never enters your mind. If the president says it's right, it's right."

He boasts of lying to Congress about the president's perks and of subverting investigators from the General Accounting Office with gifts of cuff links. He sounds very proud of himself when he tells how, using the "national security" screen, he frivolously kept the public from discovering some of the waste that was going on in the White House.

Does it now bother him that he witnessed many anti-public episodes over the years and participated in some? Apparently not. If he sometimes performed dishonest actions on behalf of the president, it was, he says, because "there is no honest way to do the things you need to do." Toward the end, excusing his indifference to Nixon's Watergate crimes, Gulley says, "I'm not in the judgment business." Do guys with that mindless creed actually last for 11 years on the White House staff? If they do, we're sunk.