Is Pulling Out of Iraq Realistic?

I am all for pulling out of Iraq and bring the troops home. I feel like we are fighting in a war and risking the lives of thousands of Americans for the wrong reasons. Barack Obama and Hillary Clinton have both said that if they should be elected to the presidency, a large majority of the troops will be coming home. While I am completely for this withdrawal, I realize the problems that could arise from such an action. A withdrawal seems to signify an admission of defeat and leaving the unstable Iraqi government to fend of Al-Qaeda by itself. Many people tend to feel that should that be the case, it's Iraq's problem. Many also believe that a withdrawal would do a disjustice to the thousands of service men and women who lost their lives fighting for our country. To make a withdrawal possible, we need to be training the Iraqi army and police force to deal with the Al-Qaeda threat. It is their country and it will ultimately turn out to be their fight. To how far an extent can American blood be spilled to further a war that never should have taken place in the beginning? I just hope that whoever the next President is, that he or she makes the right decisions on Iraq and closes the political divide present in the United States today.