For NSA, America's biggest and most important intelligence agency, this was a deeply unwelcome and uncomfortable change. For decades, the agency had gone about its top secret business with little public scrutiny or fanfare.

Out at its main base at Fort Meade, in the Maryland suburbs halfway between Baltimore and Washington, DC, NSA had long been regarded as "No Such Agency," and for many years the Pentagon indeed denied its very existence, even though its sprawling headquarters complex, where tens of thousands are employed, was visible from the highway.

While the agency no longer denies it's there, the Snowden compromise cast scrutiny on NSA of a degree and kind it had never imagined. The initial reaction at Fort Meade to Snowden was shock, then disbelief that the agency's "crown jewels" had been exposed to the world.