Why not go through FISA?

The more we know about this NSA spying program, the more irregular it seems.

As the FISA warrants are available retroactively up to 72 hours(you can start the tap with a finding by the AG then apply for a warrant within three days,) the entire administration defense, that these warrants are required for reasons of speed or agility is shown to be false.

The logical question then, assuming the administration is being disingenuous,(I know, I know) is what other reasons would they have for trying to obtain these taps outside of the FISA court. I've come across what I think are two valid possibilities.

1) The taps were wanted for individuals who were not involved in any sort of activity that might warrant such a tap. A possible example: a reporter with contacts within al qaeda or within a foreign government or intel service like Pakistan.

2) The information that prompted the desire for these taps was not obtained in a judicially admissible way either by unreliable reports or through torture. One other more benign possibility is that the administration didn't want to name the sources, but I would think that with the special conditions around a FISA court that would not be a real issue.

Take your pick. I don't like any of them.