Agreed. But when you have "John Smith" coming in over VPN from a foreign IP to a domestic email account, how can you tell if they are an expat citizen or a masquerade? Presumably this is why the NSA monitors whenever at least one half of the connection is foreign.
The number of expat citizens is small enough as to be statistically insignificant at this scale of monitoring. For all intents and purposes they can just be treated as foreigners.
I mean, what real American would ever deign to leave the homeland?! If you leave the USA to go live in some stupid foreign land you must not want your human rights anyway.
