We pulled out of Vietnam because we could not win the war for the south vietnamise. It was dragging on and not looking better, only scraficing our troops to the north. Thats why we pulled out, because everyone knew it was inevitable that the North would fight forever until we caved in and dropped the nukes, which we couldnt do. We just straight up could not win for the south because of poor strategy and many other reasons.
If people like RSR ran the country, he would believe that the US could win any war. And that my friend, is wrong. We can not win every single war and if we always thought the way you did, we would STILL be in vietnam until our very last troop was killed! Pride does not win wars.
Iraq is different, we have won the war, now we are baby sitting a monster. Thats basically a waste of time, and proves we should not have went in to begin with, Suddam did a better job of babysitting.
There is no doubt that we had a major military victory in overthrowing Saddam Hussein's government and capturing him but now we are faced with a different enemy and it is one domestic to Iraq and it is this insurgency which we cannot defeat. This isn't defeatist instead it is to acknowledge that the only way the insurgency will be defeated is if the Iraqi's do it themselves and deal with the political implications of the Civil War in Iraq. Once they have done that it will be easy for them to address the problem of terrorists coming into Iraq and undermining the political process. Our troops being there will only result in more of them dying and increasing the number of insurgents.