The terrorists that are associated with 9/11 began to operate in Iraq only AFTER Bush removed Saddam Hussein and disbanded the Iraqi military. That allowed internal and external forces to create the terrorism that rips the country daily and has resulted in 30,000 dead Iraqis and 2,150 American military deaths.
There is NO assurance that the government that emerges in Iraq after we have departed will be one that will prevent terrorists groups from operating or that we will be able to deal with in the future. If terrorist groups can operate with 150,000 U S Troops and 200,000 Iraq military present, what makes anyone believe the terrorism will end after we leave.
Iraq has only been maintained as a single country by force since its creation. First it was the power of the British and then Saddam Hussein. The three factions hate each other and it is doubtful the new government will be able to maintain stability.
The Key is NOT the elections but what type of government emerges!