"But when you weigh that against the alternative, which is not to act," he said, "you realize that some analysis is better than no analysis. Because even if your analysis proves to be wrong, the marketplace of ideas will bear that out. If you look at it from an engineering perspective, an iterative perspective, it's clear that you have to try something rather than do nothing."
By his own terms, Snowden succeeded beyond plausible ambition. Accustomed to watching without being watched, the NSA faces scrutiny it has not endured since the 1970s, or perhaps ever.
The cascading effects have made themselves felt in Congress, the courts, popular culture, Silicon Valley and world capitals. The basic structure of the Internet itself is now in question, as Brazil and members of the European Union consider measures to keep their data away from U.S. territory and U.S. technology giants including Google, Microsoft and Yahoo take extraordinary step to block the collection of data by their government.
For months, Obama administration officials attacked Snowden's motives and said the work of the NSA was distorted by selective leaks and misinterpretations.
On Dec. 16, in a lawsuit that could not have gone forward without the disclosures made possible by Snowden, U.S. District Judge Richard Leon described the NSA's capabilities as "almost Orwellian" and said its bulk collection of U.S. domestic telephone records was probably unconstitutional.
The next day, in the Roosevelt Room, an unusual delegation of executives from old telephone companies and young Internet firms told President Barack Obama that the NSA's intrusion into their networks was a threat to the U.S. information economy. The following day, an advisory panel appointed by Obama recommended substantial new restrictions on the NSA, including an end to the domestic call-records program.