"We don't keep files on every American citizen": depends how you define 'files' and perhaps there is 1 American citizen they don't keep files on, so not 'every'. But we have on sworn testimony that the NSA keeps all of your emails [1] & a large chunk of your electronic communications & spies on American citizens[2][3].
He not only said files, but also "dossiers," which is even more formal. Nothing about having huge buckets of already-collected data from which these files and dossiers can be compiled later.
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"We don't keep files on every American citizen": depends how you define 'files' and perhaps there is 1 American citizen they don't keep files on, so not 'every'. But we have on sworn testimony that the NSA keeps all of your emails [1] & a large chunk of your electronic communications & spies on American citizens[2][3].
[1] https://www.eff.org/files/filenode/att/section1006summary101... See in particular ex-NSA officer William Binney's testimony.
[2] https://www.eff.org/node/55051
[3] https://www.eff.org/deeplinks/2012/03/nsa-chief-denies-abili...
There's also the aspect about law, allowing warrantless wiretapping of anyone, or, everyone[1].
[1] http://www.washingtonpost.com/world/national-security/us-int...
He not only said files, but also "dossiers," which is even more formal. Nothing about having huge buckets of already-collected data from which these files and dossiers can be compiled later.