Why Are We Still Fighting This War?

pardon my ignorance, but I don't understand why we are still fighting this war. Why don't we bring the troops home? Are we actually intending to win something by staying there? We are in SO much debt, and the war is wasting so much money. In my town, my summer school was canceled because of the budget cuts. I know lots of other things are being cut too. I just don't understand it! this is a serious question. Why doesn't the US government end the war already?