Did you know that the Five Eyes alliance (which the US is apart of), has been noted to spy on foreigners and pass the data to their governments to bypass laws around spying on their own citizens? These things cut both ways, foucault's boomerang and all that.

Also, why do you think it's ok to spy on people without oversight just because they are foreign? Everyone is deserving of privacy. If there is legitimate reason to spy, then obtain a warrant.