It's a plan
Justin outlined it very well.
For it to be un-American it must be so regardless of success or failure. If we succeed in creating a stable democracy in Iraq it will go down in history as a brilliant strategy and WMD will be a footnote.
It is on Bush's head to make it work and that includes getting re-elected to see that his plan is carried out.
If the plan fails for any reason, it becomes a bad idea from the get-go and Bush deserves all the criticism he will get and I will be one of his harshest critics. If it succeeds it was a great plan and history will judge it that way.
I would have done the same thing for the reasons that Justin listed but only with total certainty of success. There is no room for failure and no excuses will be accepted.