The government claims that these security programs are necessary for our safety, and have cited over 50 examples wherein terrorist plots were discovered and stopped due to this surveillance. However, opponents have debunked at least some of these claims, which have been either exaggerated, or were primarily stopped via traditional law enforcement methods.

Are there any publicly known cases of a credible terrorist attack that was discovered or stopped because of large-scale wiretapping/traffic analysis/etc. playing an essential role, without which the plot would not have been discovered or stopped?

For the purposes of answering, if a plot was initially discovered by one of these surveillance programs, it will be assumed that it would not have been discovered otherwise, unless there is other evidence indicating that there was another lead from elsewhere.

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    What do you mean by solely? How are you judging causation? Are you using a but-for test? What about concurrent causes, one of which was the NSA program? Or two causes that either alone would have been sufficient?
    – user5582
    Commented Jun 27, 2013 at 21:46
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    It’s relevant here to note the distinction between targeted wire-tapping after a specific court order had been obtained – which has always been legal – and large-scale, unspecific wire-tapping, as done under Prism and related programs. The government wants to demonstrate the need for the latter but as far as I can see, so far they’ve only shown cases for the former. Commented Jun 27, 2013 at 22:02
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    "Soley" meaning that the very act of wire-tapping prevented an attack? That seems rather impossible.
    – Flimzy
    Commented Jun 28, 2013 at 1:13

1 Answer 1


As far as I know there has only been one successful "plot" foiled, involving a San Diego cab driver who gave $8,500 to an al-Qaeda affiliate(archive.org version). Note that the source may have some bias even though it claims to be nonpartisan.

  • I believe that the New America site may be down temporarily, as the Google search results route to the same error.
    – Matt Buffo
    Commented May 11, 2015 at 20:53
  • The website itself is up the link still leads nowhere. That suggest the article is withdrawn which makes it no good source.
    – Christian
    Commented May 11, 2015 at 22:41
  • 1
    It's working now
    – Matt Buffo
    Commented May 20, 2015 at 20:30

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