FILE - This Nov. 22, 1963 file photo shows President John F. Kennedy riding in motorcade with first lady Jacqueline Kenndy in Dallas, Texas. (AP Photo, file)

A key adviser warned President John F. Kennedy after the disastrous Bay of Pigs invasion of Cuba in 1961 that the agency behind it, the CIA, had grown too powerful. He proposed giving the State Department control of “all clandestine activities” and breaking up the CIA.

The page of Special Assistant Arthur Schlesinger Jr.’s memo outlining the proposal was among the newly public material in documents related to Kennedy’s assassination released this week by the U.S. National Archives and Records Administration. So, too was Schlesinger’s statement that 47% of the political officers in U.S. embassies were controlled by the CIA.

Some readers of the previously withheld material in Schlesinger’s 15-page memo view it as evidence of both mistrust between Kennedy and the CIA and a reason the CIA at least would not make Kennedy’s security a high priority ahead of his assassination in Dallas on Nov. 22, 1963. That gave fresh attention Thursday to a decades-old theory about who killed JFK — that the CIA had a hand in it.

Some Kennedy scholars, historians and writers said they haven’t yet seen anything in the 63,000 pages of material released under an order from President Donald Trump that undercuts the conclusion that Lee Harvey Oswald, a 24-year-old Marine and onetime defector to the Soviet Union, was a lone gunman. But they also say they understand why doubters gravitate toward the theory.

“You have this young, charismatic president with so much potential for the future, and on the other side of the scale, you have this 24-year-old waif, Oswald, and it doesn’t balance. You want to put something weightier on the Oswald side,” said Gerald Posner, whose book, “Case Closed,” details the evidence that Oswald was a lone gunman.

The first ‘big event’ in the US to spawn conspiracy theories

Critics of the Oswald-acted-alone conclusion had predicted that previously unreleased material would bolster their positions. One of them, Jefferson Morley, the editor of the JFK Facts blog, said Thursday that newly public material is important to “the JFK case.” Morley is vice president of the Mary Ferrell Foundation, a repository for files related to the assassination.

Morley said that even with the release of 63,000 pages this week, there is still more unreleased material, including 2,400 files that the FBI said it discovered after Trump issued his order in January and material held by the Kennedy family.

Kennedy was killed on a visit to Dallas, when his motorcade was finishing its parade route downtown and shots rang out from the Texas School Book Depository building. Police arrested Oswald, who had positioned himself from a sniper’s perch on the sixth floor. Two days later Jack Ruby, a nightclub owner, fatally shot Oswald during a jail transfer broadcast live on television.

“It was the first big event that led to a series of events involving conspiracy theories that have left Americans believing, almost permanently, that their government lies to them so often they shouldn’t pay close attention,” said Larry Sabato, director of the University of Virginia Center for Politics and author of “The Kennedy Half-Century”

The Bay of Pigs fiasco prompts an aide’s memo

Morley said Schlesinger’s memo provides the “origin story” of mutual mistrust between Kennedy and the CIA.

Kennedy had inherited the Bay of Pigs plan from his predecessor, President Dwight Eisenhower, and had been in office less than three months when the operation launched in April 1961 as a covert invasion to topple Cuban leader Fidel Castro. Schlesinger’s memo was dated June 30, 1961, a little more than two months later.

Schlesinger told Kennedy that all covert operations should be cleared with the U.S. State Department instead of allowing the CIA to largely present proposed operations almost as accomplished tasks. He also said in some places, such as Austria and Chile, far more than half the embassies’ political officers were CIA-controlled.

Ronald Neumann, former US ambassador to Afghanistan, Algeria and Bahrain, said most American diplomats now are “non-CIA,” and in most places, ambassadors do not automatically defer to the CIA.

“CIA station chiefs also have an important function for ambassadors, because the station chief is usually the senior intelligence officer at a post,” Neumann said, adding that ambassadors see a CIA station chiefs as providing valuable information.

But he noted: “If you get into the areas where we were involved in covert operations in supporting wars, you’re going to have a different picture. You’re going to have a picture which will differ from a normal embassy and normal operations.”

A proposal to break up the CIA that didn’t come to fruition

Schlesinger’s memo ends with a previously redacted page that spells out a proposal to give control of covert activities to the State Department and to split the CIA into two agencies reporting to separate undersecretaries of state. Morley sees it as a response to Kennedy’s anger over the Bay of Pigs and something Kennedy was seriously contemplating.

The plan never came to fruition.

Sabato said that Kennedy simply “needed the CIA” in the Cold War conflict with the Soviet Union and its allies like Cuba, and a huge reorganization would have hindered intelligence operations. He also said the president and his brother, U.S. Attorney General Robert F. Kennedy, wanted to oust Castro before JFK ran for reelection in 1964.

“Let’s remember that a good percentage of the covert operations were aimed at Fidel Castro in Cuba,” Sabato said.

Timothy Naftali, an adjunct professor at Columbia University who is writing a book about JFK’s presidency, discounts the idea of tensions between the president and the CIA lasting until Kennedy’s death. For one thing, he said, the president used covert operations “avidly.”

“I find that the more details we get on that period, the more it appears likely that the Kennedy brothers were in control of the intelligence community,” Naftali said. “You can see his imprint. You can see that there is a system by which he is directing the intelligence community. It’s not always direct, but he’s directing it.”