The Warren Commission, which released its report on the John F. Kennedy assassination 50 years ago, used this model to illustrate the three shots allegedly taken by Lee Harvey Oswald. (BRENDAN SMIALOWSKI/AFP/Getty Images)

Philip Shenon, a former Washington correspondent for the New York Times, is the author of “A Cruel and Shocking Act: The Secret History of the Kennedy Assassination.”

Describing someone as a “conspiracy theorist” is usually meant as an insult, suggesting tin-foil hats and babbling rants on late-night radio talk shows. But when it comes to the assassination of President John F. Kennedy, the list of important, seemingly credible public figures who count themselves as conspiracy theorists is long and impressive.

Fifty years ago this coming week, the President’s Commission on the Assassination of President John F. Kennedy, the panel led by Chief Justice Earl Warren and better known as the Warren Commission, published an 888-page final report that identified Lee Harvey Oswald as the sole gunman in Dealey Plaza and said there was no evidence of a conspiracy, foreign or domestic.

Those findings were meant to put an end to the swirling conspiracy theories about the president’s murder. Yet the theories persisted. Americans had difficulty accepting that the most powerful man in the world could be brought down by a troubled young man wielding a $21 mail-order rifle. And in the wake of the Vietnam War, Watergate and so many other scandals and national tragedies that followed the assassination, people grew increasingly skeptical that the government could be expected to tell them the truth. By the late 1960s, opinion polls showed that most Americans had rejected the findings of the Warren Commission’s report. An April 2013 poll by the Associated Press found that 59 percent of Americans believed there was a conspiracy in Kennedy’s death.

The bold-faced names among the conspiracy theorists have included the president who established the commission. Lyndon Johnson said in the final years of his life that he believed that the Warren Commission was wrong and that Cuban leader Fidel Castro was behind the assassination. Another surprising conspiracy theorist: the slain president’s brother, former attorney general Robert Kennedy, who publicly supported the Warren Report even as he told friends and family he was convinced that Castro, the Mafia or even some rogue element of the CIA was responsible for his brother’s death. Last year, Secretary of State John Kerry told a television interviewer that “to this day, I have serious doubts that Lee Harvey Oswald acted alone.”

And this month, on the eve of the report’s 50th anniversary, the roster of seemingly credible Americans willing to identify themselves as Kennedy-assassination conspiracy theorists has grown to include someone from within the Warren Commission itself: Charles N. Shaffer Jr., a former Justice Department prosecutor who served on the investigation’s staff in 1964 (he says he was dispatched by Attorney General Kennedy as “Bobby’s spy”) and went on to a headline-making career as a Washington-based criminal defense lawyer.

In interviews I have been conducting for a new edition of my 2013 book on the assassination, Shaffer told me there probably was a conspiracy in President Kennedy’s death, which makes him the first commission insider to say so publicly. He said he has no doubt that Oswald was the lone gunman in Dealey Plaza. Nor does he question the single-bullet theory, developed by the commission’s staff, which holds that one bullet passed through the bodies of both Kennedy and Texas Gov. John Connally. But he now suspects that the assassination was the work, ultimately, of organized-crime figures who somehow manipulated Oswald into gunning down the president in Dallas on Friday, Nov. 22, 1963, and then directed strip-club operator Jack Ruby to silence Oswald by killing him two days later.

“The Warren Report was an honest report, based on what we knew at the time,” Shaffer said. “But nothing should have been written in stone. There were later developments that convinced me that maybe we missed something.”

Shaffer, who maintains an active legal practice at age 82 and is perhaps best remembered in Washington for his defense of White House counsel John Dean during Watergate , said he has long been troubled by disclosures about possible Mafia involvement in the assassination. He said he was struck in particular by the account of mob lawyer Frank Ragano. In his 1994 memoir, Ragano wrote that Tampa-based crime boss Santo Trafficante confessed to him in 1987 that he and Carlos Marcello, the mob boss of New Orleans, were responsible for the assassination. According to Ragano, the dying Trafficante uttered the words: “Carlos messed up. We shouldn’t have killed John. We should have killed Bobby.”

Shaffer, who also defended powerful organized-crime figures, knew Ragano. He said he always thought the account seemed credible: It made sense that Trafficante and Marcello would have wanted revenge for the Justice Department’s aggressive prosecution of mob figures during the Kennedy administration, and they would have been in a position to order Ruby, who had a history of low-level ties to organized-crime figures, to kill Oswald. “If you credit what Ragano says, there was a conspiracy,” Shaffer said. “It sounds right.”

The mob theory has long been a popular one among conspiracy theorists, although other former commission staffers, as well as Ragano’s family and a number of independent researchers, dismiss it. Howard P. Willens, a senior member of the commission’s staff, told me he is convinced that Shaffer, a close friend, is wrong. “No number of commonly held suspicions amounts to one fact,” he said.

Burt Griffin, a retired Ohio judge who also served on the commission’s staff and was responsible for investigating Ruby’s background, said he, too, is certain there was no Mafia conspiracy. “I’ve tried to keep abreast of the allegations that the Mafia was involved in the assassination,” he told me. “It’s nonsense. Zero evidence of any contacts with Oswald.” Critics have suggested that Ragano made up his story to sell books or as an act of vengeance against his former client.

Still, the fact that a Warren Commission staffer is now challenging the investigation’s central findings creates another dent in the commission’s already damaged legacy — and will only add to the skepticism that the truth about the assassination can ever be known.

Warren bears much of the responsibility for his commission’s failures. Years later, he would admit that, in his own mind, he ruled out a conspiracy within days of the president’s murder. As a result, he frequently blocked staff lawyers from pursuing lines of investigation that might have pointed to co-conspirators.

Shaffer said he believes that Warren’s biggest blunder was his refusal to allow Ruby to testify in Washington. Ruby consistently denied involvement in a conspiracy, saying he had loved the slain president and murdered Oswald on impulse. But in a face-to-face meeting with Warren in Dallas in June 1964, Ruby, who was seen by psychiatrists at the time as delusional, if not clinically insane, pleaded to go to Washington because “I want to tell the truth, and I can’t tell it here.” Warren refused, saying he worried for Ruby’s safety in the capital. Shaffer said the decision was “ridiculous” and meant that the commission missed a “golden opportunity” to see if Ruby was prepared to expose a conspiracy.

For my book, I spoke to the surviving members of the commission’s staff and then pursued the leads they hadn’t been able to follow — because Warren resisted or because, it is now clear, evidence had been hidden from them. I was never swayed by the theories of a mob plot, if only because it seemed so unlikely that the Mafia would enlist such pathetic misfits as Oswald and Ruby in the crime of the century. I was much more intrigued by evidence — denied to the commission’s staff — suggesting that Oswald had talked openly about his plans to kill the president and that he may have been promised help if he were ever able to succeed. Much of that evidence involves his mysterious visit to Mexico City several weeks before the assassination, when Oswald, a self-proclaimed Marxist, was apparently trying to get a visa to defect to Cuba.

Both the CIA and the FBI had Oswald under surveillance in the fall of 1963. But they withheld information from the Warren Commission about how much they knew about him before the assassination. The CIA never told the commission about its plots during the Kennedy administration to assassinate Castro — plots that the Cuban dictator discovered, giving him an obvious motive to kill Kennedy. The FBI destroyed evidence before it could reach the commission, including a handwritten, apparently threatening note that Oswald delivered to the bureau’s field office in Dallas in early November 1963. On the day Oswald was murdered by Ruby, FBI agents in Dallas, fearing that the note would be seen as evidence that they had been aware of the danger Oswald posed to the president, shredded the piece of paper and flushed it down a toilet. Its exact contents remain a mystery.

So the Warren Commission record is incomplete. And conspiracy theories are likely to plague us forever.

shenon.books@gmail.com

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