The twist here is that the NSA gets to trawl through the data looking for interesting stuff (to them) on a pinky promise to a judge (in a court that has never said no) that they won't target US citizens. Given that the US government has stated that a 51% chance that the target is not a US citizen is sufficient to meet this requirement (!), it sounds to me as if the NSA gets to target whoever they like (because taking a huge pile of data and processing it with automated algorithms is not 'collecting' it according to the State doublespeak) and if they happen to wind up targeting some US citizens, well they can always claim in court (should it ever come to that, which it won't) that they thought there was a 51%+ chance that they were dealing with non-US individuals. How would you ever challenge that?