Protect America Act and Domestic Surveillance

As I speculated on 08/05/2007, the Protect America Act does in fact allow spying on purely domestic calls without a warrant. So from now on, I will be calling it the Spy on Americans Act. Some details from the draft of "Risking Communications Security: Potential Hazards of the “Protect America Act”," authored by Steven M. Bellovin, Columbia University, Matt Blaze, University of Pennsylvania Whitfield Diffie, Sun Microsystems Susan Landau, Sun Microsystems, Peter G. Neumann, SRI International, Jennifer Rexford, Princeton University:

While most traffic on international links travels to or from a foreign host, a small amount of domestic traffic traverses these links as well. For example, some domestic traffic travels through Canada and then back to the U.S., due to the vagaries of Internet routing11. As such, monitoring the links at the U.S. borders, with the goal of warrantless tapping of international traffic, could lead to unintentional tapping of domestic traffic. Because these links operate at very high speed, it is difficult to analyze the measurement data as they are collected. Furthermore, Internet traffic does not necessarily follow symmetric paths — the traffic from host A to host B does not necessarily traverse the same links as the traffic from B to A —monitoring both ends of a conversation sometimes requires combining data collected from multiple locations, making this type of monitoring
difficult in practice.

And this is with the assumption that NSA is making a good faith effort to not intercept domestic calls. There are other complications as well, I suggest checking out the whole piece linked to above.