One way to keep track of the intensity of the War on Terrorism the increase in the number of reserve and National Guard troops called to active service. The total on active duty has been slowly increasing each month. As of mid June, the total was 85,415. An invasion of Iraq would probably require about twice that number. The 1991 Gulf War saw a quarter million men and women activated. But there are not as many combat units to support this time around, so that many people will probably not be needed. The reserves and National Guard mainly supply support troops.