After we kill/arrest Saddam and his family and top henchmen, we're not just going to "give up and leave". While no concrete plans for administration have been made just yet, I believe that a U.S. or NATO general will end up temporarily administering the government (like MacArthur in Japan), with a popularly elected government to come within the next 2-5 years. Heck, they may even decide to split up Iraq into two or three separate sovereign countries. But we're going to have a military presence there for a while. And once we are in control, Iraq will be permantly removed as a possible base of any terrorist operations. And the Islamofascists won't be strengthened by our victory any more than Al-Queda has been strengthened by our operations in Afghanistan.
I would love to see a discussion of those possibilities and the risks involved in them. That's what disturbs me most about the rush to war, we aren't talking about what long term benefit it will have versus the long term risks.