Citizens at the border have a lowered expectation of privacy. This is well-known and understood principle of national sovereignty (protecting a border is one o

Citizens at the border have a lowered expectation of privacy. This is well-known and understood principle of national sovereignty (protecting a border is one of the core principles of being a soverign entity). So the 4th amendment doesn't apply to border searches as a routine search is not an unreasonable one to (re)gain entry. Making an international call to a business associate from Chicago to Cairo seems pretty obvious that I have as reasonable expectation to privacy as I do calling my business associate in New York. So, the answer is yes the Constitution does require a standard. The specific standard of probable cause is up to the judiciary to determine not found in the Constitution. I suppose if I was calling a known terrorist organization or conducting business in a war zone I would know that I have a much lowered expectation of privacy, for example. FISA was simply a way to avoid the national security implications and backdoor the judiciary oversight by setting up a "fake" judiciary. Apparently we can't even trust public elected officals in Congress or on the bench to keep the public's interest in mind as they would divulge national secrets to the national enquirer at first opportunity or whatever. Not like we can trust the checks and balances on the legislative branch to function as intended </sarcasm>. The concept of secret police and oversight by secret courts would be repugnant to the founders and should be to any citizen. Regarding the obtaining of communications between foreign nationals of which no citizen is a party, I have less to say. Espionage and counterterrorism is a dirty and necessary game played by every nation but conducting as wide a sweep as what is implied here in my opinion is bad policy because the cost to diplomacy and normal trade relations between nations is much too high. It invites and even necessitates a response that is chilling.