On the battlefield it's a recipe for disaster.
This restriction of foreign to foreign wiretaps if the communications passes through US territory is from a July 2007 ruling by a FISA judge. It is a really stupid ruling and it is costing us a lot of valuable intelligence (including in this case).
http://topics.nytimes.com/top/reference/timestopics/subjects/f/foreign_intelligence_surveillance_act_fisa/index.html
That would be the Commander-in-Chief, George W. Bush.