It's a known fact that USA has participated in various wars. To name a few: Spanish War, World War II, Korean War, Vietnam War and recently War against Terrorism. So, I think it's okay to specify about war. --Ramesh.
Version 2 of this page claimed a similar deleterious effect from the September 11 terrorist attacks as the Great Depression and the US Civil War. I suspect that's an exaggeration - either way, it's too early to tell. I'm not claiming that September 11 wasn't a very important event, and I mean no disrespect to the thousands who died. It's just that the other events are even more important. --Robert Merkel