I'm sure that the defense attorneys will use that reasoning, as they should, but I just don't see it going anywhere post-Patriot Act.
I think that's a slam dunk winner. Or even getting calls from suspected (not known) terrorists (not just al Qaeda) abroad.
I suspect any issues will relate to "probable cause" as to how the government concluded (in the first place) that the "foreigner" (could be a US citizen overseas, in a global sense) is apt to engage in a conversation that represent a foreign intelligence interest. If it reached that conclusion in the first place based on secret surveillance, the case is a harder one to get past a judge. It resembles "precrime," where any and all surveillance is justified, based on the "successes" where surveillance is the only activity that creates the reasonable suspicion.