The failure to release more files by Obama’s self-imposed December 2013 deadline is blamed on several factors; the most important may be that an array of federal agencies retains what amounts to a veto. Any agency can stonewall the release of any document that includes information it generated, no matter how old it is.

Four years after President Obama pledged to preside over the most transparent government ever — a vow that included declassifying as many documents as possible contained in the so-called backlog — the majority are still secret.

COLLEGE PARK, Md. — A half-hour’s drive from the White House, nestled between leafy residential neighborhoods, rests a massive repository of America’s classified documents, from the mundane to deepest secrets of the Cold War. In all, some 352 million pages line the shelves.


As a result of this and other restrictions, the National Declassification Center in College Park has been able to pry open only a portion of the huge backlog of historical documents about military strategy, intelligence operations, and a host of other secret government actions never fully scrutinized by historians, researchers, or the media.

Of the 134 million pages it has been able to process, nearly half will remain secret, according to officials — despite the fact that most of the documents were subject to “automatic” declassification deadlines that have long passed.

Even some officials reviewing the declassification process say the overall approach is not working.

“The current system is simply not capable of addressing the vast volume of information,” said Nancy Soderberg, chairwoman of the Public Interest Declassification Board, an advisory committee established by Congress in 2000 to promote access to government documents. “It requires agencies to be willing to take a small additional risk for much more benefit.”

She said the requirement for the National Archives to refer all declassification decisions on historical information to one or more national security agencies is significantly slowing down public access.


Sheryl Shenberger, founding director of the National Declassification Center — which was established by Obama in 2009 — has confronted the bottleneck frequently since the new unit began working with some 30 separate agencies that have purview over national security information.

Agencies have often asserted that entire categories of documents, despite repeated reviews, were not properly evaluated and therefore could not be declassified.

“It can happen every few weeks,“ Shenberger said in an interview. “That could affect 100,000 pages, literally, because a whole series will be killed.”

Shenberger said when she receives those responses her staff members “go in the stacks, they pull the boxes, they open it up and they look at the documents. I think we have a really good success rate with having them change their minds.”

The National Declassification Center also attributes some of the continued delay to simply the time-consuming nature of reviewing so much paper with few available technical tools to help ensure that genuinely sensitive information is properly identified.

“It is unfortunate that because this is all hard copy there is only so much technology you can apply to this,” said Shenberger, a former CIA official.

Another factor, discovered when the center began its work in early 2010, is that many of the historical documents had been subject to widely divergent — and often shoddy — handling procedures by the agencies that shipped them to the National Archives. In some cases, staff found that even some of the most secretive intelligence agencies made little effort to determine which secrets should be kept.


“So the records come in here and you’d like to think all the agencies . . . had done a good job,” Shenberger said. “The reality of the situation was there were for the most part varying degrees of good to very bad.”

Shenberger said that officials concluded it would be impossible to review everything. So the center established a sampling process, reviewing 10 percent of individual collections at a time, to assess whether crucial national security data had been properly identified before arriving at the National Archives.

“All of the 352 million pages have been dealt with,” she said. “We know the stuff that can be declassified.”

But that doesn’t mean that the bulk of documents will be available to researchers anytime soon, even though many are subject to regulations requiring they be automatically declassified — after 25 years, 50 years, or 75 years, depending on the subject matter. (A host of exemptions are allowed for certain categories, such as information about individual spies.)

With the ultimate declassification authority still in the hands of the national security agencies, a process that was supposed to be relatively quick and automatic has often become slow and cumbersome.

Agencies such as the Department of Defense, the State Department, and the CIA are under little pressure to approve their documents for public release and, according to experts knowledgeable about the classification system, are predisposed to keep raw files locked away.


For example, more than a half-century later, one secret episode that has not been fully disclosed is the CIA-orchestrated coup in Iran in 1953 that toppled the democratically elected prime minister, Mohammad Mosaddegh.

“There has been an effort over a period of years to assemble documents that would fill in many of the gaps about the 1953 coup,” said Stephen Kinzer, author of “The Brothers: John Foster Dulles, Allen Dulles and Their Secret World War.” “There are huge holes and it is quite clear a lot is missing. It is way overdue.”

Another controversy surrounds the final — and still withheld — volume of the CIA’s official history of the failed 1961 Bay of Pigs invasion of Cuba by US-trained exiles. A federal appeals court last week sided with the agency, which maintains the volume should remain secret because it was only a “draft,” not a complete document.

Peter Kornbluh, who heads the Cuba Documentation Project at the National Security Archive at George Washington University, which filed the lawsuit seeking the volume’s release, said it is just one example of how national security agencies resist opening up their historical files.

“The people that keep the secrets are not team players” with the National Declassification Center, he said.

Several agencies declined to discuss their declassification procedures. A spokeswoman for the Department of Defense, which has contributed some of the most voluminous collections, declined to make anyone available to answer questions, referring a reporter to the National Declassification Center.


Some experts contend that the only way to ensure public access is for the president to give broader declassification powers to the National Archives. Leaving declassification decisions to the agency that generated the document “totally destroyed the whole concept behind automatic declassification. There is nothing automatic about it,” said J. William Leonard, former director of the Information Security Oversight Office, which oversees the government’s classification system.

Steven Aftergood, a specialist on government secrecy at the Federation of American Scientists, agreed. He suggested Obama sign an executive order stipulating that if agencies don’t declassify something after a set period of time, the center be given the authority to act.

“It should not be held hostage to an agency that is unable or unwilling to fulfill its responsibility,” Aftergood said.

In a statement, the White House maintains that the National Declassification Center remains “at the core of the president’s efforts . . . for transforming the security classification system.”

Laura Lucas Magnuson, a spokeswoman for the National Security Council, called “significant” its efforts to meet Obama’s goal, including streamlining key processes and coordinating with dozens of agencies.

But executive branch officials also acknowledge more needs to be done. In a December 2013 action plan, the White House laid out new goals for encouraging greater openness, including calling for a review of how historical data covering sensitive subjects like nuclear weapons could be more easily declassified.

“There is a lot of discussion going on to at least be able to review the nuclear stuff such as on the Cuban missile crisis,” Soderberg said. “A lot of the information there is still classified that is of immense interest to historians and most agree it could be put out there.”

But she doesn’t believe Obama is in a position to force the issue by taking the power to declassify away from the national security agencies, because “it would probably backfire on him. You would have a revolt on your hands in Congress.”

Meanwhile, as the National Declassification Center plods ahead, more historical documents are piling up: since January 2010, another 33 million pages.

Bryan Bender can be reached at bender@globe.com. Follow him on Twitter @GlobeBender