Vines, the NSA spokeswoman, said there was no record of those conversations, either.
Just before releasing the documents this spring, Snowden made a final review of the risks. He had overcome what he described at the time as a "selfish fear" of the consequences for himself.
"I said to you the only fear [left] is apathy — that people won't care, that they won't want change," he recalled this month.
The documents leaked by Snowden compelled attention because they revealed to Americans a history they did not know they had.
Internal briefing documents reveled in the "Golden Age of Electronic Surveillance." Brawny cover names such as MUSCULAR, TUMULT and TURMOIL boasted of the agency's prowess.
With assistance from private communications firms, the NSA had learned to capture enormous flows of data at the speed of light from fiber-optic cables that carried Internet and telephone traffic over continents and under seas. According to one document in Snowden's cache, the agency's Special Source Operations group, which as early as 2006 was said to be ingesting "one Library of Congress every 14.4 seconds," had an official seal that might have been parody: an eagle with all the world's cables in its grasp.
Each year, NSA systems collected hundreds of millions of email address books, hundreds of billions of cellphone location records and trillions of domestic call logs.
Most of that data, by definition and intent, belonged to ordinary people suspected of nothing. But vast new storage capacity and processing tools enabled the NSA to use the information to map human relationships on a planetary scale. Only this way, its leadership believed, could the NSA reach beyond its universe of known intelligence targets.
In the view of the NSA, signals intelligence, or electronic eavesdropping, was a matter of life and death, "without which America would cease to exist as we know it," according to an internal presentation in the first week of October 2001 as the agency ramped up its response to the al-Qaida attacks on New York and Washington.