Simply put, the National Security Agency is an intelligence agency. Its purpose is to monitor the world's communications, which it traditionally collected by using spy satellites, taps on cables, and placing listening stations around the world.
In 2008, by making changes to U.S. law, the U.S. Congress enabled the NSA to make U.S. industry complicit in its mission. No longer would the NSA have to rely only on international gathering points. It can now go to domestic companies who hold massive…