I don't think I said that. I think maybe you're reading the phrase "an association which is a foreign power" to mean something other than what it actually says. It means the association itself is the foreign power. The phrase doesn't say "IN association with a foreign power". It says "AN association which IS a foreign power".
Look at the definition of association:
1. The act of associating or the state of being associated.I think you're reading the word "association" as though it has meaning #1, when meaning #2 is the proper one.
2. An organized body of people who have an interest, activity, or purpose in common; a society.
I don't think I said that, either. The six meanings of foreign power defined in 1801(a) aren't all mutually exclusive. For example, "a foreign government or any component thereof" could also be a "a group engaged in international terrorism".
Are you then saying that it is a violation of FISA to conduct warantless electronic surveillance against terrorists?
No. I'm saying that if a terrorist isn't a foreign power as defined in 1801(a)(1-3), then section 1802(a) wouldn't be applicable. 1804 would be the applicable section.
My original and main point, however, was to correct your assertion that a U.S. person is not a U.S. person if he's an agent of a foreign power.