The idea that you can't have surveillance of a US citizen who is communicating with suspected terrorists is ludicrous on its face.
I remember....a long time ago....some kind of a discussion that CIA is foreign, FBI is domestic intelligence. I'm guessing there has to be some kind of overlap to make surveillance effective that is not being properly noted.
Regardless....There is a FISA site you can visit. It's very informative.
Schummer and Kyle were very active in this. Shummer=Hillary's Boot licker.
Common sense tells me that neither the courts or Congress can prevent the President from doing what is necessary to protect the country. The President might agree to take some additional steps, but those steps can, in no way, be binding.