March 27,2008: So far, the U.S. has spent $636 billion on its military response (the Global War on Terror ) to the September 11, 2001 attacks. Iraq has taken 64 percent of this, while Afghanistan (and other locations, like Djibouti and the Philippines) have used 15 percent. The other 21 percent was spent on Homeland Defense. That comes to about $10.6 billion a month. This pays for 256,000 troops deployed overseas (for 2007) and 46,000 activated reservists in the U.S. The military, particularly the army, is using the war to develop and purchase a new generation of weapons and equipment. To that end, in the last five years, over $100 billion has been spent on procurement, and about $5 billion on R&D (not counting $8 billion spent on developing stuff to deal with IEDs.) But perhaps the most important gain from the war are the hundreds of thousands of combat experienced troops. These will insure a high degree of combat readiness in the army and marines for a generation. It currently costs about $390,000 to send a soldier overseas to Iraq or Afghanistan for a year.