WASHINGTON — They’d been waiting 25 years to see the final – and potentially most sensitive – batch of records related to President John F. Kennedy’s assassination. Then came word late Thursday that President Trump had acquiesced to CIA and FBI lobbying to withhold tens of thousands of the files.

For historians, journalists and Kennedy buffs, the promise of revelations about what happened in Dallas on Nov. 22, 1963 disappeared.

“My expectations were low, and they should have been lower,” said Gerald Posner, author of the 1993 Kennedy assassination book, “Case Closed.”

Though the National Archives and Records Administration put 2,800 records online, about 30,000 more remain concealed at the urging of national security officials.

On Friday, WikiLeaks offered $100,000 for the still withheld documents. On Twitter, the organization’s founder, Julian Assange, polled followers over Trump’s about-face.

“Why did U.S. intelligence agencies fail to meet the legal deadline they had 25 YEARS NOTICE OF for the release of all remaining JFK files by today?” he asked. The choices: “Show power over Trump,” “Ruin Trump’s PR move,” “Serious incompetence” or “Conceal activities.”

Early Friday, the president tweeted assurances to those infuriated by the delay that he wants to disclose as much as possible: “JFK Files are being carefully released. In the end there will be great transparency. It is my hope to get just about every thing to the public!”

Peter Kornbluh, a Cuba specialist at the National Security Archive at George Washington University, said he, too, was frustrated because the government had 25 years to make the deadline imposed by the President John F. Kennedy Assassination Records Collection Act of 1992. The law required that all the records “shall be publicly disclosed in full.”

But the act came with an asterisk, allowing the president to withhold documents beyond Oct. 26, 2017, if he decided disclosure would harm national security.

“I have no choice – today – but to accept those redactions rather than allow potentially irreversible harm to our nation’s security,” Trump wrote in a memo Thursday night.

Many leading Kennedy experts weren’t buying it.

Kornbluh, the Cuba authority, said most of the papers that were released didn’t warrant the long-held secrecy. He pointed to a never-before-seen memo by J. Edgar Hoover, dated two days after the assassination. Hoover says in the memo that he wanted to have “something issued so we can convince the public that Oswald is the real assassin,” and that he thought the investigation should be kept secret because of Oswald’s contacts with the Cuban embassy in Mexico City and the Soviet embassy in Washington.

“What is the secrecy around that document really about?” asked Kornbluh, who co-authored a 2014 book on the United States’ secret diplomacy with Cuba called “Back Channel to Cuba.”

For Kornbluh, some of the more intriguing documents in the entire Kennedy collection were not released Thursday. He was hoping to see the files on Luis Posada Carriles, who had been given explosives training by the CIA as part of the Bay of Pigs invasion and was later implicated in several terrorist attacks.

“We could learn the degree to which he worked for the CIA, his operations and the whole history of how he left the CIA, and went to Venezuela to plan the bombing of a Cuban airliner in 1976 that killed 73 men, women and children,” Kornbluh said.

He was intrigued by some released records Thursday, including a 1975 report by White House counsel Philip Buchen, who summarized the CIA’s assassination plots against foreign leaders.

Some of the more eye-popping details included a proposed government operation to induce Cubans to overthrow their government, with financial rewards for various types of Cuban leaders: up to $100,000 for government officials, and perhaps for symbolic reasons, 2 cents for Castro.

“The price list appears to be new,” Kornbluh said. “I think it is one of the most comprehensive summaries of real and proposed assassination operations against Castro that I have ever read, and I have read all of them.”