I think the NSA mindset is if the data is collected and stored, but not looked at by human eyes is neither a search, a wiretap or even a breach of privacy. For furthermore when you place a telephone call, there is a connection made with a bandwidth of 64 Kbd (base 10 64K) of which 56Kbd are used for the bearer channel or B channel, which carriers the voice or private part and 8Kbd data channel, or D channel which carriers the switching information, the public part. The D channel is public because the data is necessary to route the phone call. Thus to the NSA if they intercept a phone conversation, they can store, but not listen to the B channel, analyse the D channel all they want. If the NSA determins that the communications is between non-US citizens to a confidence level greater than 50% they can listen to the B channel if they choose to, if the confidence is less than 50% then they have to get a warrant.