The goal would be to get a permanent injunction barring the activity until such time as laws were passed making it legal. In the US system of laws its the way folks force someone to stop doing something when that someone is more than an individual (you can't put a corporation in jail but you can tell them that if they do something you will put their leadership in jail [an imperfect analogy])
"you can't put a corporation in jail but you can tell them that if they do something you will put their leadership in jail [an imperfect analogy])"
Does leadership, from a corporation either private or government (NSA, CIA, FTC, etc) ever end up going to jail though? It seems like after the banking industry was pretty much caught red-handed breaking all kinds of laws and/or causing all kinds of programs to end or start, none of them ended up behind bars. I have to think the NSA would be better at avoiding jailtime than bankers...
Maybe I'm just pessimistic but it seems more like the best this could hope for is the NSA stopping Prism and then finding out 5-10 years later (or never) that they started Diamond or some other program that does the same thing except doesn't record the first 5 seconds of phone calls, or something else that "obeys the new rules"...
If the suit succeeds, wouldn't ratifying the Constitution be the only way to actually make it 'legal'? A law the infringes on the rights of the people without due process cannot be remedied by any other number of laws except where those laws reduce the scope to those wherein more narrow warrants are granted (I think).
And if such laws do get passed, the people who wrote and supported them would be open to voter backlash, which is why they were done using secretive "guidelines."
