Edward Snowden didn't just take a bunch of documents and run, anonymous government officials tell the AP—he first covered his digital footprints, bypassing the NSA's own safeguards and electronic logs so the agency has no record of what he's seen or downloaded. That's a problem for the Obama administration, because it has been defending its surveillance programs to Congress with assurances that the NSA monitors and reviews everything employees are doing, so there is no opening for abuse. But if Snowden could get around the NSA's internal security system, it raises the question: how many others can, too?
The NSA will not say whether it knows exactly what Snowden has. A spokesperson says the agency's director has "a sense of what documents and information had been taken," but "he did not say the comprehensive investigation had been completed." If Snowden does know how to hack or obfuscate NSA security, it could make him a valuable resource for foreign governments. It could also explain why UK authorities recently seized the laptop of Guardian journalist Glenn Greenwald's partner, posits the AP—as the US and UK governments may not actually know what the paper still has on them.