The NSA has released a full statement in response to The Guardian's leak of more classified data coming out of the NSA. The subject at hand is a program called "XKeyscore," which is purported to be a centralized interface for NSA employees to access a wide array of data from email, browsing history, and more. In the leaks, the system appears to show broad access to such data whether or not the target is a US citizen.
The NSA's response, which mirrors much of the language it had previously given The Guardian, stresses that the NSA is only targeting "legitimate foreign intelligence targets." The NSA further argues that it is not allowing "widespread, unchecked analyst access" to this data, but that analysts must go through "appropriate training." Finally, the NSA contends that its "tools have stringent oversight and compliance mechanisms" and that "no analyst can operate freely" without audits from above.
The NSA repeated its contention that it has captured "over 300 terrorists" thanks to XKeyscore as of 2008, and warns that leaks of this nature are "detrimental to the national security of the United States." The difficulty, of course, is whether we can ever truly know how much oversight there in for a secretive system in such a secretive agency. If there's a silver lining to be found for privacy advocates, it's that XKeyscore reportedly only keeps the content of emails and similar data for three to five days — though such content can be moved to a more permanent database should the NSA deem it appropriate.