A recent poll asked servicemembers in Iraq about their reasons for being there, and the results (at RadioBlogger.com) have been discussed at Castle Argghhh (check the comments) and Villainous Company, among other fine places. FOr some reason, it all reminds me of Mark Twain and "there are lies, damned lies and statistics".
I’m in Iraq because I believe the attack on September 11th, 2001, ushered in a new era for terrorism. I agreed that it was best to “go global” right then and establish lines of demarcation across our humble little planet, clearly exposing those who stand against terrorism and those who would harbor and aid terrorist groups.
You really need to go read the whole thing.
Then go read some of the other fine posts from Lieutenant K at his blog. Like Leadership and Parenthood, or A Letter to the Republic for Which We Stand (II), or just start at the top, and work your way down.