First, that was seven years ago and yes, I believed that Saddam was pursuing a biochemical or nuclear weapons program that threatened the United States. I also believed that the U.S. could spread liberal democratic values to Iraq. Turns out I was wrong on both counts.
Second, non-interventionism and isolationism are different; I don't want the U.S. to become isolationists, I want us to sign trade agreements and be active in supporting global commerce. I just don't think we need to go around and spend our (as a local right-libertarian talk show host puts it) blood and treasure on silly jingoistic military adventurism.