The NSA concerns were outlined in top-secret documents provided to the Senate and House intelligence committees in February 2012, well before Snowden emerged this summer as the sole source of massive new disclosures about the agency's surveillance operations. The Post released only 17 pages of the entire 178-page budget document, citing conversations with Obama administration officials who voiced alarms about disclosures that could compromise intelligence sources and methods.
Shawn Turner, director of public affairs for the Office of the Director of National Intelligence, who has taken the lead in responding to the Snowden disclosures, did not immediately respond to a request to discuss the budget figures.
It was not clear from the Post's reporting how many of the 4,000 potential insider threats were ultimately investigated or how many posed serious breaches of security. Steven Aftergood, head of a project on government secrecy at the Federation of American Scientists in Washington, questioned whether many of the reported 4,000 possible leaks were credible cases.
Referring to previous reports that the NSA's classified work force totals nearly 40,000, Aftergood said, "It would be hard to believe that one in every 10 NSA employees is a possible threat." He suggested that many cases might be caused by internal warnings arising from minor internal protocol errors or mistakenly accessed documents.
But aggressive high-profile Justice Department prosecutions in recent years of several former NSA staffers have shown the agency taking a toughened stance in cracking down on possible leaks. "In any case, a number that large is striking," Aftergood said.
The latest revelations also disclosed limited details about the highly classified 2013 intelligence "black budget," which previously only provided a topline of nearly $53 billion. The $52.6 billion intelligence budget described by the Post discloses that the NSA's portion was $10.5 billion in 2013 — outstripped only by the CIA's $14.7 billion.
Aftergood said the CIA's budget growth from $3 billion in the 1990s to nearly $15 billion likely reflects its post-9/11 push into drone warfare and paramilitary operations overseas.