>How exactly does that make it okay to walk away from a growing self-governing democracy unable to protect itself from terrorists?

Iraq is country occupied by foreign armies that govern the country. It is not a democracy, since they Iraqi government cannot ask the US (and the Brits) to leave.

More Iraqi's are dying post invasion than pre-invasion. http://news.bbc.co.uk/2/hi/middle_east/3962969.stm
Is that what you call protection?