From analysing intelligence to training new spies, jobs that were once performed by government employees are now carried out by paid contractors, in a dramatic shift that began in the 1990s amid budget pressures.
Edward Snowden, the 29-year-old man behind the explosive leak, is among a legion of private contractors who make up nearly 30 per cent of the workforce in intelligence agencies, a staggering growth that accelerated in the years since the attacks of September 11, 2001.
The contractors who wear a "green badge" to enter government offices may lack the ethos and discretion of career intelligence officers who wear the "blue badge," according to John Schindler, a former analyst at the National Security Agency and counterintelligence officer.
In a series of tweets, Schindler, who now teaches at the Naval War College, heaped scorn on Snowden for leaking the details of the NSA's surveillance of phone records and Internet traffic.
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"Been telling my CI (counter intelligence) peeps for years that NSA & IC (intelligence community) only 1 disgruntled, maladjusted IT dork away from disaster (esp IT contractor)...Oh well," he wrote.
Systems administrators are the equivalent of the Cold War-era "code clerks" of the 21st century, he said, as they may not hold a high rank or engage in espionage but they have access to vital information.
Most contractors are former military or intelligence officers, and America's top spy chief, James Clapper, once worked at Booz Allen Hamilton, the same firm that employed Snowden. Another former national intelligence director, Michael McConnell, also worked at the firm before and after holding the director's post.