Don't know much about FISA. The only thing I do know is that there is a judge somewhere that authorizes wiretap warrants. Whether under FISA or any other legal provision. Do they have secret judges? Who knows.

With FISA the NSA even comes into play. Where "National Security" interests are concerned.. they can do whatever they want basically. If you are going to bring a case into court that is where all the legalese has to be in order. Otherwise the case will get thrown out and the government's efforts to prosecute will be down the drain.