Quoth the Alex in comments: "Something that's interesting is that the War on Terror has now gone on longer than America's involvement in WWII. December 41 - August 45 versus September 01 - May 05. Of course, in the former, those 3.7 years saw 400,000 soldiers killed. So it's comparing apples to oranges."

A more appropriate comparison would be War on Terror to War on Drugs, or War on Poverty, or War on any other conceptual thing that is completely unwinnable in any practical sense. You can compare the Iraq War (still going!) to WW2 or Nam or what have you, but the War On Terror is just a stupid rhetorical device.