This is why've were trying to make it legal lately. They were already doing it. The same thing happened with the Patriot Act.
It seems FBI/NSA "test-drive" a new illegal spying program first, and then lobby Congress to pass a law to make it legal (regardless of its constitutionality, as we've seen so far).
I bet they would've wanted retroactive immunity, too, in these new laws. Also, let's see how those supporters of FISA, like Dianne Feinstein, try to spin this one as "they already knew about it" (which makes it that much worse) and that it's nothing new.
Also let me see them say with a straight face that this is constitutional and doesn't violate the 4th Amendment. But seeing how cynical these people have become, I don't think it would be too hard for them to do it.