The parent poster should have been more specific. The reason lawsuits have largely be stymied has been the claim of state secrets (whether or not everyone in the room knew the program existed, the executive branch argued that details would reveal things that would be detrimental to the state) and because no one who sued could prove they had standing to sue because no one knew who was actually being monitored.
So, yes, we knew section 215, FISA, etc existed, but no one has been able to (yet) successfully challenge them fully because any legal basis for challenging has been (in many cases actively) kept secret.
