Just some thoughts on U.S. war capability

For a long time the U.S. had a policy of keeping a standing military ready to fight one full war and one half war at the same time. This means that the U.S. can engage in one all out war in one region, while still being able to do peacekeeping missions and smaller scale operations in other regions at the same time. There was a time when people viewed the need for this with skepticism. Following the Persian Gulf War, some believed the world was becoming more united and less tolerant of rogue states.
After 9/11, many began to realize that the proper approach was neither a single war policy or a war and a half policy. So the U.S. adopted a two war policy. This allowed the U.S. to fight the Iraqi War and the Afghani War at the same time. Of course, here comes my criticism.
I've got the sense that the U.S. is barely able to fight one all out war right now. It seems to me that the politicians and bureaucrats have significantly underestimated the resources required to fight a war. It's my opinion that the current chaotic situation in Iraq could've been avoided had we sent in the appropriate number of forces from the beginning. In additional, the Afghani War never got significant U.S. forces at all. In reality, it was a half of a war. So, the U.S. really is fighting and rebuilding nations from one and a half wars. Yet, our ability to do this was based on trying to implement a two war policy. It seems to me that maybe our leaders don't really have a sane grasp of reality when it comes to what's really involved when fighting a war. We haven't learned from many of the biggest mistakes in the Vietnam War. Mistakes like never making a formal declaration of war, underestimating the enemy's ability to stay entrenched, or working too closely with the existing powers within the occupied nation. We succeeded with reforming Japan and Germany, but these were two nations weary of wars they started. Right now, we are occupying one nation that is weary of the war we started, and another nation that's not had a strong central government in modern times.
These wars need to be finished. In my mind, the Afghani War will not be done until Bin Laden & crew is captured. This should be our main focus. We should've been fighting the Afghani War as a full war. We need to get Iraq on its feet so we can finish our job in Afghanistan.