re: It's a little unfair...
It isn't just Iraq where the Left has come up short on ideas. The Left had no workable policies for dealing with terrorism in general, as seen by the last ten years.
After 9/11, other than reflexively invoking the United Nations at every opportunity (an organization raking in cash from people like Saddam and placing terrorist nations in charge of human rights), there really wasn't anything there at all in the way of alternatives.
It isn't surprising that they are now reduced to kibitzing from the sidelines.