The N.S.A. is not just intercepting the communications of Americans who are in direct contact with foreigners targeted overseas, a practice that government officials have openly acknowledged. It is also casting a far wider net for people who cite information linked to those foreigners, like a little used e-mail address, according to a senior intelligence official.
While it has long been known that the agency conducts extensive computer searches of data it vacuums up overseas, that it is systematically searching â€” without warrants â€” through the contents of Americansâ€™ communications that cross the border reveals more about the scale of its secret operations.
It also adds another element to the unfolding debate, provoked by the disclosures of Edward J. Snowden, the former N.S.A. contractor, about whether the agency has infringed on Americansâ€™ privacy as it scoops up e-mails and phone data in its quest to ferret out foreign intelligence.
Government officials say the cross-border surveillance was authorized by a 2008 law, the FISA Amendments Act, in which Congress approved eavesdropping on domestic soil without warrants as long as the â€œtargetâ€ was a noncitizen abroad. Voice communications are not included in that surveillance, the senior official said.
Asked to comment, Judith A. Emmel, an N.S.A. spokeswoman, did not directly address surveillance of cross-border communications. But she said the agencyâ€™s activities were lawful and intended to gather intelligence not about Americans but about â€œforeign powers and their agents, foreign organizations, foreign persons or international terrorists.â€
â€œIn carrying out its signals intelligence mission, N.S.A. collects only what it is explicitly authorized to collect,â€ she said. â€œMoreover, the agencyâ€™s activities are deployed only in response to requirements for information to protect the country and its interests.â€
Hints of the surveillance appeared in a set of rules, leaked by Mr. Snowden, for how the N.S.A. may carry out the 2008 FISA law. One paragraph mentions that the agency â€œseeks to acquire communications about the target that are not to or from the target.â€ The pages were posted online by the newspaper The Guardian on June 20, but the telltale paragraph, the only rule marked â€œTop Secretâ€ amid 18 pages of restrictions, went largely overlooked amid other disclosures.
To conduct the surveillance, the N.S.A. is temporarily copying and then sifting through the contents of what is apparently most e-mails and other text-based communications that cross the border. The senior intelligence official, who, like other former and current government officials, spoke on condition of anonymity because of the sensitivity of the topic, said the N.S.A. makes a â€œclone of selected communication linksâ€ to gather the communications, but declined to specify details, like the volume of the data that passes through them.
Computer scientists said that it would be difficult to systematically search the contents of the communications without first gathering nearly all cross-border text-based data; fiber-optic networks work by breaking messages into tiny packets that flow at the speed of light over different pathways to their shared destination, so they would need to be captured and reassembled.
The official said that a computer searches the data for the identifying keywords or other â€œselectorsâ€ and stores those that match so that human analysts could later examine them. The remaining communications, the official said, are deleted; the entire process takes â€œa small number of seconds,â€ and the system has no ability to perform â€œretrospective searching.â€
The official said the keyword and other terms were â€œvery preciseâ€ to minimize the number of innocent American communications that were flagged by the program. At the same time, the official acknowledged that there had been times when changes by telecommunications providers or in the technology had led to inadvertent overcollection. The N.S.A. monitors for these problems, fixes them and reports such incidents to its overseers in the government, the official said.
If you are shocked, don’t be. Â The Atlantic said all of this would be happening in 2011.Â