Talking to some of my conservative friends it seems one of their biggest issues is the US looking bad being run out by what they call "Al Quada thugs"
It is crucial to frame the withdrawal argument as a victory. It should go something like this:
We overthrew Saddam and liberated Iraq. That was our mission and we've completed it, Iraq is free of WMD. We are not occupiers, it's time to come home. We won in Iraq.
THe strongest argument the Republicans have is that Democrats are advocating surrender, we're not. We are advocating victory.