You start with the premise that this war, to install a government at odds with the local culture, could be won.
I find that to be in err.
And yet we did it in Japan.
The idea that we couldn't win in Afghanistan or Iraq is incorrect. We certainly could. We could impose our will, impose a humane constitution, impose democracy of some kind, etc. All that is required is the willingness to be as viscous and brutal as our opponents (or more so) and otherwise rule with an iron fist. The Japanese people (and Germans) knew we'd take out whole cities if necessary to win. We didn't play games trying to separate the people from the government, we went to war under the assumption that the Japanese (and German) people were responsible for their own government. We went to war with a people, and we demonstrated the will to kill even hundreds of thousands of civilians without sitting around fretting about who was a combatant and who wasn't.
In Afghanistan (and Iraq), the people know we are not really, completely serious about victory. Under those circumstances it will be damn near impossible for much good to come of things in the long term.
While I do not like Ron Paul at all (I mostly consider him a loon), he does make a good point about getting formal declarations of war before we march off to battle. I don't agree with him that the congressional authorizations aren't sufficient, they are. But I do agree with the serious statement that a real declaration of war would provide. We should be fighting these wars to win at whatever the cost, or not at all.
Unlike here, where they start with the premise that they can install a government at odds with the local culture without firing a shot...