This ...
"The President has inherent constitutional authority as Commander in Chief and sole organ for the nation in foreign affairs to conduct warrantless surveillance of enemy forces for intelligence purposes to detect and disrupt armed attacks on the United States. Congress does not have the power to restrict the President's exercise of this authority."
... has been the rule forever. It appears in SCOTUS cases ("the Keith case") and elsewehre, and is the reason FISA was created - to fool the people into belief that snooping was "always" pursurant to a personalized warrant. LOL - hardly. Big Brother is real.
Your right, I only posted a portion of what I found about secret surveillance and didn’t even touch the Patriot Act or FISA.
May the Fourth Amendment to the Constitution (1789-2001) RIP!
Key word is enemy. Warrantless surviellance of US persons is against the Constitution hence the requirement for FISA. If Big Brother or his mionions is/are unlawful then when the SOB hangs from a post he shoulda known it was coming.