(CNN) No one will remember in years to come where they were when they heard about the JFK assassination classified document dump of 2017.

In the end, what was supposed to be the final release of government secrets about the 1963 killing of President John F. Kennedy wasn't quite the blockbuster splash that President Donald Trump had been promising.

In fact, a day of intrigue and behind-the-scenes maneuvering by US intelligence agencies is likely only to feed the notorious conspiracy theories that the release of the historical trove was designed to quell once and for all.

It's 54 years since Kennedy died and a quarter century since Congress decreed Thursday as the day when all classified records related to the assassination should be thrown open to the public.

Trump, with an impresario's flair, had been building it up for days, as though he was promoting one of his Miss Universe pageants rather than a fresh perspective on one of the most traumatic moments in US history.

At the center of his own self-directed drama, Trump, a noted peddler of conspiracy theories and who is prone to secrecy himself, especially over his refusal to release his tax returns, was going to strike a famous blow for transparency and blow the lid off everything the government was still hiding over what happened in Dallas on November 22,1963.

"The long anticipated release of the #JFKFiles will take place tomorrow. So interesting!" Trump had tweeted on Wednesday.

Once the 2,800 documents finally hit the website of the National Archives at just after 7.30 p.m., there were some fascinating historical nuggets surrounding Kennedy assassin Lee Harvey Oswald, his murderer Jack Ruby and even a tantalizing walk-on part by Marilyn Monroe.

But the bigger story lay in what is still missing, unknown and secret.

The big reveal didn't live up to its billing because spy agency officials successfully pleaded with Trump to hold back 300 or so files, forcing him to set up yet another classified review process -- this one lasting six months.

The drama around the release of the documents was like so much of Trump's nine months in power, involving a big promise that he struggled to fulfill and a rush of last-minute chaos inside the White House.

There was also a glimpse of the tenacious bureaucratic blocking maneuvers favored by big centers of power in Washington -- in this case the CIA and the FBI -- that have made it so difficult for Trump to drain the swamp.

Friday, Trump couldn't commit to full disclosure of every file.

"JFK Files are being carefully released. In the end there will be great transparency. It is my hope to get just about everything to public!" he tweeted.

JFK Files are being carefully released. In the end there will be great transparency. It is my hope to get just about everything to public! — Donald J. Trump (@realDonaldTrump) October 27, 2017

Cynics have suggested all along that the spy agencies would intervene to leave at least some of the historical record surrounding the assassination obscured.

They were right. With the clock ticking down to the deadline on Thursday, the spooks jammed the White House with hundreds of last-minute requests for redactions, leaving the President with an impossible choice to either release everything and further alienate the espionage community, or allow himself to be strong-armed by his own spies.

Given that the FBI and the CIA have been able to see this moment coming for 25 years, it's difficult to see the last-minute requests for secrecy as anything but an attempt to perform an end run around the President.

"I think it's shameful," CNN chief legal analyst Jeffrey Toobin said. "This is something that the intelligence agencies have had not years, but decades to deal with."

He added, "This instinctive desire to keep things secret is so engrained, that even relating to events in the early 1960s, the idea that they can't be released at this point is absurd."

Defenders of the intelligence community argued that some of the information at issue could center on US informers and intelligence assets in places like Cuba and Mexico who could still be alive and at risk of reprisals.

It's also possible it could embarrass intelligence services which still have a relationship with the US clandestine community.

But such is the never-ending swirl of intrigue and and grassy knoll conspiracy theories around the Kennedy assassination that any equivocation by the government was certain to set off the rumor machines again.

"Withholding this stuff is just going to add to the crazy conspiracy theories and they are everywhere," Robert Baer, a former CIA operations officer who is now a CNN intelligence and security analyst, told CNN's Erin Burnett.

Roger Stone, the political provocateur and Trump ally, quickly blamed the "deep state" for covering up damaging information.

"The issue is it shows the treachery of the Central Intelligence Agency who recruited (Lee Harvey Oswald), who trained him and who placed him," Stone told CNN's Jeremy Diamond.

Earlier, Stone had tweeted: "The truth is out there. #JFKFiles #LBJKilledJFK http://bit.ly/LBJKilledJFK."

The White House made clear that Trump was not happy that his plans for a comprehensive document release failed to pan out, with a senior White House official admitting that the process had been "messy."

"He was unhappy with the level of redactions," another White House official said, adding that Trump believed the agencies were "not meeting the spirit of the law."

White House press secretary Sarah Sanders added in a statement that Trump "has demanded unprecedented transparency from the agencies and directed them to minimize redactions without delay."

Given the 11th-hour intervention by the spy agencies, no one would bet that the White House can avoid a similar mess next April when Trump's review process is due to conclude.

JUST WATCHED Historian: Evidence of cover-ups in Oswald case Replay More Videos ... MUST WATCH Historian: Evidence of cover-ups in Oswald case 02:22

Still, among the 2,800 documents released Thursday, there was some intriguing bounty to feed the Kennedy assassination industry.

A 1975 report indicated that the CIA attempted to hire mobsters to kill Cuban leader Fidel Castro.

In an memo, then-Attorney General Robert Kennedy was warned that a forthcoming book would allege he had an affair with Monroe.

One of the documents included a transcript of a conversation involving J. Edgar Hoover in which the then FBI director revealed that the bureau had received a call the night before nightclub owner Jack Ruby shot Oswald, warning that the Kennedy assassination suspect was a target.

It also contains details of Oswald's contacts with the Soviet embassy in Washington and conversations in Mexico City, that offered information about his state of mind.

"Hoover is explaining why he does not want an independent investigation of Ruby's killing of Oswald, and of Oswald's killing of the President," said CNN Presidential historian Timothy Naftali.

"It just shows you the level of federal bungling and the extent to which the FBI, within two days of Kennedy's assassination, was already thinking of a cover-up, not because it had killed Kennedy but because it hadn't done what it should have done to protect the President."

There is also testimony from former CIA director Richard Helms, saying that President Lyndon Johnson used to say that the reason Kennedy was shot was that he had ordered the assassination of President Ngo Dinh Diem, the president of South Vietnam.

Raising some eyebrows as well: records from a 1975 deposition to the Rockefeller Commission with a lawyer probing Helms on potential CIA involvement in a variety of global assassination attempts who asked whether Oswald might be connected to the CIA.

"Is there any information involved with the assassination of President Kennedy which in any way shows that Lee Harvey Oswald was in some way a CIA agent or an agent..." before the document suddenly ends, without his answer.

The sense that secretive institutions deep in the US government still, all these decades later, have something to hide, will only be exacerbated by the 300 documents that Trump held back on Thursday.

The JFK conspiracy theorists just got a new lease on life -- for six months at least.