For the past three weeks in the gray stone solemnity of the U.S. Courthouse here, somebody's been lying.

And the jury that retires Friday to decide the verdict in this bizarre drug conspiracy case will have to determine who it is: the government witnesses who named defendant Richard Stratton as the operator of an airborne narcotics dealership; or Stratton, a prote'ge' of Norman Mailer, who admits he consorted constantly with smugglers--but only as research for the novel-in-progress Stratton calls "investigative journalism."

The story that has unfolded beneath the rain-stippled windows and peeling pilasters is more than most writers could ask for. Half a ton of marijuana and hashish stashed in the woody fastness of rural Maine. Panicked night flights to remote airstrips in Quebec. A rancorous cabal of smugglers; oddball monikers, including Fred Barn Swallow, Bald Eagle and the Three-Eyed Weasel; coded assignments made at midnight from pay phones; briefcases stuffed with $100 bills. A wall-sized Nazi flag covered with knives and hatchets. A fierce and protracted courtroom skirmish that saw appearances by Mailer and historian Doris Kearns and then subsided abruptly with the defendant's last-minute decision not to take the stand.

And at the center of it all: Richard Lowell Stratton, 37, facing up to 15 years on a charge of "conspiracy to possess with intent to distribute marijuana and hashish." He was one of 15 persons arrested in March 1982 after police seized an estimated $1.5 million in drugs from a hamlet near the 160-acre farm Stratton owns jointly with Mailer. Eventually, 10 negotiated guilty pleas; two people were acquitted and two others fled. Stratton--a sometime contributor to Rolling Stone and High Times magazines and a researcher for Mailer's book "Marilyn"--maintained his innocence, while conceding that he not only knew the smugglers but even helped load a plane and flew on a delivery to Canada.

It was all part, he argues, of a five-year project "to penetrate the upper echelons of the international drug-smuggling business," which led him from the great "hippie families" in America to their sources in the Middle East and South America, uncovered corrupt U.S. "double agents" and involved Stratton in a "deep cover operation" with a U.S. government agent--Defense Intelligence Agency or CIA, he still isn't sure. ("I can never reveal these sources," Stratton wrote in a memorandum to the court. "If forced to name confidential sources and contacts, I cannot testify in my own defense.") The result is "Drug War"--the first volume of a projected trilogy bankrolled by a convicted Canadian drug figure, encouraged by Mailer and now represented by the Scott Meredith agency.

From the outset, Stratton had sought to focus the trial on his credentials and prerogatives as a writer, counting heavily on the testimony of Mailer and Kearns.

By the time Mailer arrived in court this morning, there was standing room only for the first time in the trial. When Judge Edward Gignoux genially pointed this out, Mailer replied, "I don't know whether to feel honored or chastened."

Mounting the witness box with a rolling ursine gait, Mailer at first seemed self-conscious, his voice a halting gargle as he described meeting Stratton 12 years ago in Provincetown, Mass., where he found him "a bit of a daredevil" with "a lot of moxie" who proved a surprisingly good boxer ("I took a left hook I'll never forget").

Growing increasingly loquacious, Mailer explained how he had hired Stratton as the caretaker of a 160-acre Maine farm Mailer then owned with author Richard Goodwin, how Stratton eventually bought out Goodwin's share, and how during the mid-'70s Stratton was at work on "a long novel." Under cross-examination, Mailer conceded he had not seen Stratton or the farm during the period of the alleged conspiracy (October 1981 to April 1982) and knew none of the other figures allegedly involved.

Afterward, outside the courthouse, an ebullient Mailer, rocking rhythmically on his heels in a crush of cameras and reporters, said he had been "surprised but not startled" when he first heard of Stratton's arrest: "Part of our friendship is that we're both foolish." But he said Stratton's association with criminals was typical of "any investigative reporter," and praised the manuscript's "marvelous detail" and "great knowledge of the marijuana trade."

Inevitably, the nagging analogy arose between Stratton and Jack Henry Abbott, Mailer's notorious last prote'ge', a convict-author who published a prison memoir, "In the Belly of the Beast," and then was convicted of stabbing a waiter to death. After Abbott was convicted last year, Mailer publicly took the blame for the "absolute tragedy, hideous waste and horror" of the episode. That is why, Mailer said, during a previous visit to Portland "I told Richard, 'You need me like you need a hole in the head,' since if there's any recognition to my name at large, it's associated with Jack Abbott."

"Don't you have a bad reputation," one reporter asked Mailer yesterday, "for standing up for criminals?"

"I have a GOOD reputation for standing up for criminals," Mailer shot back. "Unfortunately, it's unsuccessful."

Kearns, author of "Lyndon Johnson and the American Dream," had been the first witness for the defense Tuesday morning, testifying that she and her husband, Richard Goodwin, had known Stratton and his wife for 10 years as "close friends," and had numerous discussions with Stratton about his fiction. At first he was "frustrated" and "wanted to have a world he could write about"; but having chosen drug smuggling as his subject, he gradually "became more and more absorbed in the story he was following . . ." They often discussed his "danger of crossing over the line," Kearns said. Asked after her testimony if she thought Stratton had crossed the line, Kearns said, "I just don't know."

The next defense witness was to be Stratton himself, whose direct testimony and cross-examination were expected to last at least three days. But only minutes before he was to take the stand, he abruptly informed the court he would not testify. Defense co-counsel Marshall Stern of Bangor explained that Stratton has also been indicted in Canada and is presently the subject of a grand jury investigation in New York City--both of which were "so inextricably intertwined" with the Maine case that Stratton would have to invoke the Fifth Amendment so often that he could give "no evidence of any use."

There was some speculation that the sudden and conspicuous arrival in the courtroom of two men identified as Canadian narcotics agents--burly bearded figures identically dressed in royal-blue sweatshirts, gold neck chains and blue jeans--might have influenced Stratton's move. But Stratton, interviewed later in jail, said he made his decision because the government "wouldn't limit the latitude of what they would question me on," and might ask him about his foreign contacts or knowledge of major New York drug figures. "I'd be put in the position of betraying confidences and putting myself and my wife in danger," he said. "I have evidence so damaging against U.S. government agents that I'd have to be looking over my shoulder for the rest of my life."

"I'm not on trial for what I did," Stratton says, "but for what I know." Therefore, "I'd rather do the time and keep my mouth shut."

Still, "I've never sold any drugs to anybody"; and when caught at the thin perimeter where curiosity meets crime, "I never crossed it. My personal definition of crossing the line is either planning or being an active participant for profit in the outcome. The only stake I had in the operation was the material."

U.S. Attorney Richard S. Cohen and Assistant U.S. Attorney Joseph Groff argued precisely the opposite, centering their case on the testimony of three main witnesses: Michael Sanborn, a convicted drug dealer and former cocaine addict who claimed, through four days of faltering, stuporous responses, that Stratton had been his "boss" in the Canadian smuggling scheme; William Brunton, a one-time employe of Stratton's who reluctantly described how he and Stratton, months before the period covered in the indictment, had loaded an airplane with drugs; and Robert Lewis, a Long Island pilot who testified that Stratton had hired him repeatedly to fly drugs over the Canadian border and characterized many of the personalities in and around the alleged conspiracy, including a mysterious mechanic whose head was shaved except for a single lock in back and whose house contained the wall-sized Nazi shrine.

Cohen, a brusque man with a persistently vexed look and eyelids that sag like an insomniac bloodhound's, took more than a week to complete the roster of government witnesses, slowed by the defense counsel's constant barrage of objections. The prosecution tried to assemble a comprehensive picture of Stratton as an active operative in a complex smuggling scheme, bolstered by a bevy of airplane rental, telephone and motel receipts.

The mood at the Cumberland County Jail, with its cheery western three-rail wooden fence outside, is somewhere between Joseph Wambaugh and "Animal House." Through the melee of caterwauling drunks and milling cops, Stratton saunters into the visiting room like the prime boarder at a bad hotel, a fat cigar crooked in his right forefinger. A platinum-haired woman visitor asks for an autograph, proffering the back of her checkbook register.

Dense slabs of muscle, pumped and taut from daily workouts, push at the short-sleeved sweatshirt; he was once a promising wrestler. "That's where I got these ears," he says, touching a flap of puckered gristle. "In fact, this trial is like wrestling in a seven-day tournament with Uncle Sam--and he's got so many hands, too!"

Only the veal-like pallor of his skin (prisoners are never allowed outside, and "it makes you feel like a vampire") betrays the fact that he has been here since August, when he failed to appear for a pretrial conference and his share of the farm--put up as collateral against $75,000 bail--was seized by the government, thus dispossessing his wife, stepdaughter and, incidentally, Mailer. Stratton, who says he was in California reviewing Napa Valley pot crops for High Times and meeting with his "deep cover" contact, blames the incident on missed phone calls.

Born in Boston and raised in Wellesley, Stratton comes from decorously bourgeois origins: His father ("a real Yankee trader") a professional golfer turned antique dealer; his mother "an aspiring writer," he says, from a less fluorescent limb of the famous Lowell family tree.

He started smoking pot in high school and still does. "Good marijuana is a tremendously good substance, given to man for a special purpose. Coptics believe that when you smoke it you're closer to God. And to a degree, I believe that . . . I believe very strongly in God and Jesus--he's with me throughout." And he is intrigued to have read that "He and the Apostles may have been hash dealers and smokers themselves."

In prep school he won a wrestling scholarship to Arizona State University, but left after his freshman year obsessed with becoming a writer. "I was very much influenced by Hemingway, as so many young people are," and headed for Europe. On Majorca he met Gabriella Rennie, a Belgian-born married woman some 20 years his senior with three children. She left her husband to follow Stratton back to the United States (thus "presenting me with a fully bloomed family when I was only 21") and they were married several years later.

"She's a very mysterious woman," Stratton muses, the thick-veined hand rising again to his ear. "She's never told me how much money she has or how old she is or anything." The thought seems to please him.

By 1971 he was writing his first novel, a murder story that was "really about the decay of the '60s flower children set in Harvard Square. Once I finished it it was no good." Still, he got a fellowship to the Provincetown (Mass.) Fine Arts Work Center, supporting himself with carpentry jobs. There he met Mailer, who hired him to work on the farm Mailer then owned with Richard Goodwin, who would later become Stratton's legal adviser on the "Drug War" project (and thus, because of attorney-client privilege, did not testify at the trial).

Goodwin and Mailer proved durable patrons. When Rolling Stone needed someone to do an interview with Mailer, Goodwin suggested Stratton and the result was published in 1975, earning Stratton a second assignment--an expose' of Roshdale College in Toronto, the notorious "college without rules" that had become a center of drug dealing. While there, he met Robert (Rosie) Rowbotham, a major drug figure (convicted of smuggling in 1977 and now under indictment again in Canada) who commissioned Stratton to write a book about his life.

A contract was drawn up and Stratton says Rowbotham's payments eventually totaled $200,000, paid periodically in cash, in exchange for a percentage of the royalties. "I had no hesitations at all about taking money from him. I'd rather have it spent on my writing project than on champagne and meals. And I've watched him spend more on one meal than I could make in a week!"

Once indicted, Stratton first intended to defend himself. "A moment of madness," he calls it now, which did not amuse the court. He eventually engaged Brooklyn trial lawyer Ira London and co-counsel Marshall Stern of Bangor. His legal fees, Stratton says, are being paid "by friends of my family," and will not elaborate.

London, a dapper and compact figure in snug-fitted, ventless suits and aviator glasses, rarely resisted a thespian flourish. Cross-examining Sanborn, who negotiated pleas in the Stratton and other cases, London would play broadly to the jury ("Is it fair to say that it was only your hope of a reduced sentence that brought an adept liar of 15 years to this courtroom?") and convulsed even Gignoux by asking, "Would it be fair to say that a short person might get lost if he stepped into the carpeting in your house?"

Although neither London nor Stern said he was aware of a legal precedent for the "investigative research" defense, they originally considered arguing that Stratton's intimate contact with drug-world figures was analogous to Hunter Thompson's joining a motorcycle gang to write "Hell's Angels" and Gay Talese's undercover activities for "Honor Thy Father" and "Thy Neighbor's Wife." Both names were floated by the attorneys as possible witnesses, along with Ken Kesey, Carl Bernstein, Bob Woodward and others. But the defense eventually limited the list to Mailer and Kearns--both of whom knew the defendant personally. And when Thomas Heffernon, the lawyer who had drawn up the book contract between Stratton and Rowbotham, was prevented from testifying because he admitted that he had never seen it signed, the writers'-rights argument all but disappeared from the trial. It was mentioned only in passing during London's dramatic closing argument: "The fact that Richard Stratton is a writer does not entitle him to be found not guilty. But it does entitle him to be in certain places at certain times."

At 7 a.m. in the gray jailhouse morning, Stratton is slicing discs of banana with the edge of a fork into his bowl of Total. He is recounting his first arrest (New York, 1977, while covering a drug bust for High Times; charges dismissed), his alternate means of self-support (representing the Texas real-estate interests of a consortium of Arab investors he met through a friend of his wife's), his contacts with groups such as California's Brotherhood of Love, expeditions to Mexican and Lebanese marijuana fields, and the net purport of his book.

"What I learned is that at a certain level in the international drug-smuggling business, there is a lot of complicity on the part of American intelligence agents as well as foreign governments. I don't say that's with the agreement of Washington." But "it's no coincidence that just before the war in Lebanon, this country was flooded with Lebanese hashish." The revenues, Stratton says, were routed back to finance arms for pro-American military groups. "It's like Uncle Sam was looking the other way." But why, after five years of purported high-level contact, did he need to "investigate" the comparatively trivial activities of local smugglers? "Well," says Stratton, "a lot of the first book is about Maine."

According to his outline, the first volume, set in 1978, introduces the protagonists, detective Arthur Grimm ("a graduate of Harvard Law School" who "prefers running his highly successful detective agency specializing in drug-related investigations to practicing law") and Bernard Wolfshein (a DEA agent "looking into charges of anti-Semitism within the agency") who encounter "the attempted takeover of marijuana, hashish and cocaine distribution by an ultra-right wing faction of renegade government agents with ties to the International Nazi Movement." (The investigative reporter has attached to his outline a photocopied article from the tabloid National Examiner: "Nazis Flooding U.S. With Drugs.")

A portrait of one such renegade, a corrupted Canadian officer, opens Chapter 13: "The broad shouldered, blond haired man sat behind the wheel of the leased four-door sedan and looked through the dark lenses of his aviator's sunglasses at the sleek Aerostar crouched on the tarmac beside the Butler Aviation Terminal at Boston's Logan airport. Nice bird, he thought, admiring the arrow-like lines. He twisted his bushy moustache and did some quick calculations in his head.

". . . God knows, money is what this life is all about, thought Chris, cold, hard cash, pure and simple. With money you could do anything you wanted. Money was freedom, money was power. Women sucked-up to men with money. And other men were more afraid of men with bucks than they were of men with muscles . . ."

"I never had a tendency toward literary writing," Stratton says. "My stuff tends to be action-type narrative. I was brought up watching movies, not reading books."

Mailer, asked by reporters what he thought of the book, paused only momentarily before gamely declaring that "It's better than I thought it would be. I wouldn't guarantee that it's publishable, but it's pretty good." Jack Scovil of the Meredith agency is more bullish: "It's not intended to be a literary piece of work, but it's a damn good story," with "great commercial possibilities."

Stratton's possibilities appear rather more limited. Even if acquitted here, he still faces possible indictment in New York, as well as the charges in Canada, where his wife has also been indicted.

At the jail, the crowded visitors' room has become fetid. Stamped-metal ashtrays skitter on the tabletops and pushed-back chair legs screech at the floor. "Yeah," Stratton says, blue gaze dropping to the grimy linoleum, "they may extradite me right away. More than likely I won't even have one day's freedom. And there's no Bill of Rights up there. American law? It's a great system." A stubborn ironic grin cracks his face. "After all, that's why I'm here. To preserve and protect the American way--free enterprise.