It was late 1977 when the DC-3 lowered its landing gear onto a jungle airstrip, one of dozens on the Caribbean side of Colombia. The plane was to be loaded with two tons of marijuana, and then immediately turn back for Florida. But Colombian soldiers stormed the clearing, pulling an unlikely gringo from the cockpit. “Self,” thought Robert Platshorn, a 34-year-old American, as he closed his eyes on machine guns and green berets, “how in the hell did you end up here?”

It remains the preoccupying question of his life. Platshorn bribed his way out of Colombia, he says, but in May 1979, he was indicted as the mastermind of the biggest marijuana ring ever uncovered, a paramilitary squad responsible for the DC-3 job and much more—a million pounds of Santa Marta Gold between 1976 and 1977. The 105-page indictment had “more intrigue than ten James Bond novels,” as the Chicago Tribune put it: 13 codefendants, $300 million in earnings, a dozen yachts, a fleet of aircraft from a Cessna to a Lear jet, all of it coordinated from the penthouse of Miami Beach’s largest hotel, the Fontainbleau.

Platshorn was the first marijuana dealer to be prosecuted under the so-called Kingpin Statute, a 1970 law that targets elaborate large-scale drug syndicates. He was sentenced to 64 years in prison, making him “America’s longest serving marijuana prisoner,” according to High Times. This is a man “with no social conscience,” the head of Miami’s FBI office told a reporter at the time.

Now 69, Platshorn says the magnitude of his crimes was a fraction of what was accused, and casts himself as the first casualty of the war on drugs. “Kingpin?” he says by phone from his home in West Palm Beach. “I was not even a safety pin.” He makes the case in the Black Tuna Diaries, a self-published prison memoir he has been promoting since his parole in 2008, and next month in the documentary Square Grouper, which makes its television premiere on Showtime on April 20.

But it’s not all history yet. Though he’s traded aviator shades for a more senior style, Platshorn is still in the marijuana game, using his infamy for a kind of sweet revenge: legal weed. Since last fall, Platshorn, who is Jewish, has been on a “Silver Tour” of Florida synagogues and retirement homes, including his own Golden Lakes Village, stumping for medical marijuana as a first step toward outright legalization. “It’s prescribed in Israel!” he told a crowd at Temple Shaarei Shalom in Boynton Beach earlier this year. The first “Silver Tour” billboards went up in Pompano Beach this week, a late night infomercial is in the works, and several city council meetings are on the calendar. As Platshorn sees it, weed is an effective medicine for much of what ails the elderly population, which is also the largest demographic stumbling block to wider marijuana reform. Win them over and legalization may follow.

“Old people vote,” he says of his target audience, “and no one was out there educating them about marijuana.”

Platshorn’s arguments for legalization are not new, but he is an exceptional advocate. The son of a Philadelphia shoe salesman, he went right to work, spending 15 years hawking Remington automatic knives and Vita-Mix blenders on the Atlantic City boardwalk and on fairgrounds nationwide. Briefly, he was one of the nation’s top distributors of Breyer’s vanilla bean. But by 1976 marijuana seemed to be the emerging market. President Carter supported the repeal of federal laws against simple possession. So Platshorn moved to Miami and pulled a chain of connections that landed him in Santa Marta, Colombia, where he says he was far from “the biggest and slickest” smuggler that the government later described.

He says he organized only four successful smuggles: two by plane, and two by boat. A third boat sank, and a fourth load was seized by authorities in North Carolina before his Colombian connection disappeared altogether. In all, Platshorn claims, he smuggled about 100,000 pounds of marijuana, or 1/10th the number the government alleged at trial, and the Drug Enforcement Administration continues to tout on its website.

Even the FBI agent who worked the case with the DEA, Dick Moehl, agrees with Platshorn about the scale of his smuggles. “It’s probably all we agree on,” he told the Daily Beast by phone. “I had counted up about 100,000 pounds … I don’t know where the 500 tons came from.” According to a review of court documents, the 500 tons was based on the testimony of a single government informer—and the jury never ruled on a specific weight.

Still, Platshorn was hardly innocent. He expected to get a three-to-seven-year sentence, and be paroled even sooner—a reasonable expectation for even multiton marijuana crimes at the time. What he didn’t realize was how surely times had changed since his first trip to Colombia. In December 1977, Jimmy Carter’s head of drug policy, Peter Bourne, reportedly snorted coke at a Christmas Party thrown by the National Organization for the Reform of Marijuana Law. When the story broke the following summer, Carter stopped talking about marijuana reform and sent a first-of-its-kind FBI/DEA task force to Miami to stop marijuana smugglers. “We were going to start the war on drugs,” remembers Harold Copus, another of the FBI agents assigned to the case.

Platshorn and his crew was the first bust by Operation Banco, as the joint task force was known. They were dubbed the “Black Tuna Gang,” after the alleged code name of the group’s Colombian supplier, and the trial was a five-month circus of strange happenstance and eye-catching allegations. Several months in, Platshorn was accused of plotting to obstruct justice by bribing a juror and assassinating the judge, forcing a mistrial. (He was later cleared of both charges.) “This is the most bizarre, gigantic operation I have ever seen,” said one FBI agent at the time. And indeed Platshorn was hammered from the bench. “The price for participation in this traffic should be prohibitive,” said Judge James Lawrence King at sentencing. “It should be made too dangerous to be attractive.”

Perhaps not surprisingly, Platshorn tells a larkier version of events. The government said the gang had operated an intelligence unit using high-tech mobile scanners; Platshorn says it was just two buddies in a van full of Radio Shack gadgets. The government said the gang had acquired their own airstrip, a dozen yachts, a private army to defend their loads from theft by rival gangs, and had planned to hijack a 737 jet for the ultimate smuggle. Not so, says Platshorn: the airstrip, armada, and private army are sensationalized descriptions of mundane partnerships, and the 737 plan was nothing more than a “campfire chat.” Dennis Cogan, who defended Platshorn’s childhood friend and closest partner in the gang, says the allegations in the case were “so totally crazy.” “It made for good theater,” adds Arthur Tifford, who represented Platshorn against the obstruction charges. “With all due respect, persons in the executive branch needed headlines.”

Judge King declined to comment on the case, but Dana Biehl, one of the government’s prosecutors at trial, was willing to revisit it for the first time. In a recent interview with the Daily Beast, he also remembered it as a highly political case. “It’s hard to think about now, but what terrorism was after 9/11 drugs were at that time.” At first, the evidence suggested Platshorn and his partner Robert Meinster were “midlevel” players, Biehl says, and he offered them 10 years in jail. Before the plea deal could be accepted, however, it was rescinded by Washington, according to the defendant’s lawyers, and the case turned into a tentpole event for promoting government’s anti-drug efforts. Biehl argued for a life sentence at trial.

Today, he says he can certainly see why that might seem harsh. “These guys didn’t ruin the number of lives that [heroin and cocaine traffickers] Frank Matthews and Nicky Barnes did, and they were not shooting all around.”

John F. Brown Jr., the youngest lawyer on the government’s side, offers a similar view. “I don’t recall any proof that [codefendant Robert] Meinster and Platshorn ran a hard-nosed organization whose modus operandi included the use of the types of violence one would associate with, say, the Colombian gangs.” Rather, “they seemed more like the Keystone Cops than slick masterminds.”

While he was behind bars, Platshorn’s parents, sisters, and daughter died, and he and his wife divorced. “I don’t have the words,” he says about the losses he has suffered. He would rather talk about his causes.

For the first time in Florida, there are medical-marijuana resolutions in both the Senate and the House, and at least one poll shows majority public support—thanks in no small part to Platshorn. “We have a lot of seniors in our community and people with terminal illnesses that truly believe they derive relief from medical marijuana,” state representative Jeff Clemens told the Sun-Sentinel recently. Last January, after Platshorn pitched him on the idea, Clemens introduced a medical marijuana bill in the House. This year Clemens has joined Platshorn on the Silver Tour.

With Republican majorities in elected office, it’s still a long shot for marijuana legalization, medical or otherwise. But Platshorn is optimistic. Ever the salesman, he raises extra capital by selling Black Tuna Gang medallions on his website. The gold ones have sold out. Act now, however, and the silver could still be yours. “Everybody who said Florida is impossible,” says Platshorn, “doesn’t know what a pitchman can do.”