Potentially we can though. Why is our first reaction to hamstring our intelligence agencies and deny them information other entities doubtless already have? Why not instead work out how to provide them the information in a way that both protects our rights and enables them to do what we pay them to do?
> Why is our first reaction to hamstring our intelligence agencies and deny them information other entities doubtless already have?
Because history, that's why. FISA -- in its original form, not the "War on Terror"-era "FISA Amendments Act" -- was a limitation on government surveillance power which criminalized all sorts of surveillance except in very narrow circumstances, that was adopted not because of theoretical concerns but because of widespread, notorious, abuse of the national security intelligence-gathering capabilities of the US government for political purposes by the executive branch of the United States government, particularly during the Nixon Administration.
These limitations were weakened through the FISA Amendments Act on the excuse that the limitations were "hamstringing" our intelligence agencies and jeopardizing our national security (after it became publicly clear that, in fact, the limitations were being widely ignored, and the current administration wanted legal cover for actions that it was already undertaking despite the law), and, hey, look what we see -- massive, unfocussed, broad-spectrum surveillance of exactly the type we were assured wouldn't happen if we loosened the reins a bit so that the executive branch had the tools it supposedly needed to focus on direct threats from terrorists without overly burdensome constraints.