Pulse, The

Sometime in 2009, a group of terrorists detonated a nuclear bomb 80 miles above the western U.S.  This sent out an electromagnetic pulse that erased all data on any computers in range.  Since almost all of the United States financial and other important data was on computers, this had the effect of making the U.S. a third-world country.  In the chaos that followed, the government became corrupted to a new level, and most cities were blocked off, restricting travel, and other freedoms that used to be taken for granted.