A target's phone call, e-mail or chat will take the cheapest path, not the physically most direct path - you can't always predict the path
Dates When PRISM Collection Began For Each Provider
This is complete conjecture, but this reads to me like the NSA set up its own backhauls and set up peering agreements at artifically low prices to get traffic going over their pipes. Is there historical data for route announcements available anywhere? There are a lot of specific dates that could confirm/disprove this.
This is expounded upon in some news articles, particularly that data is routed not by the most efficient geographic route but by the cheapest by dollar price.
It's a very important tidbit of information that divulges the heart of the matter -- the NSA is a backbone operator[1]. It's a tall claim to make, however their involvement in internet exchange points (and other regional network access points) would be far more difficult to conceal.
Acquire access to major routers, send routing commands, route target traffic into their hidden networks, and avoid physically wiretapping anything. And this framework can be done globally:
Your target's communications [...] flowing into and through the U.S. is as easy as announcing BGP route advertisements globally.
Actually the Great Firewall of China started investigated realtime and fine-grained control of national routing infrastructure as early as in 2003.[1] This allows them to apply routing policies to routers national-wide in seconds. One observable effect is that a single address can be null routed immediately after failure to get blocked by TCP resets. It is believed the HTTPS MITM of Github last time was also helped by this routing framework. And the GFW is viewed by the Chinese government as a national security framework. No wonder the USG is doing the same thing.
[1]: Liu, G., Yun, X., Fang, B., Hu, M. 2003. A control method for large-scale network based on routing diffusion. Journal of China Institute of Communications: 10.
Dates When PRISM Collection Began For Each Provider
This is complete conjecture, but this reads to me like the NSA set up its own backhauls and set up peering agreements at artifically low prices to get traffic going over their pipes. Is there historical data for route announcements available anywhere? There are a lot of specific dates that could confirm/disprove this.