How exactly is it in our interests to leave Iraq?

Let's see we leave Iraq and hand over the entire country to some radical muslim extremists after we just spent billions overthrowing there government and installing a new one. Yep let's do that. Let's turn the middle east into an islamic super state composed of Iran, Iraq, and Syria. Why? Because we hate Bush. That's using your head. And we'll do it under the guise of supporting our troops and being pro-American. Yep let's do that. We'll call for our troops to come home because its a tough fight, but we'll ignore Japan, Germany, etc. Other countries where we have had soldiers stationed for HALF A CENTURY. Yep. This is a good plan.