The other issue I'm reading in this that is even a bit more disturbing than what's being discussed in the media is that the FISA court was being used for this, even though this is not under the purview of FISA - the warrant is to surveille IS citizens, not foreign agents. This should have gone through, at the very least, federal courts for a warrant, not the FISA panel.
Ie, FISA was used against citizens. One fear civil libertarians have been screaming for a while.