First do what nobody seems to have done at the top, study in depth as many historical examples of areas made up of several ethnicities already engaged in a bloodbath while occupied by a foriegn (and at least somewhat disliked) power as possible. Then read Liddel Hart's Strategy. And maybe Keegan's A History of Warfare. Then meet with army, corps, and divisional commanders to get their realistic perspective of what is happening in Iraq, INSISTING to, for instance, the divisional commanders that they must speak with total candor, holding nothing back out of respect for the chain of command. Then form a rational grand strategy for the war on terror and a rational strategy for Iraq.
It's a fairly common take on things, that areas that are ripe for ethnic violence are typically prevented from doing so by an occupying empire. The Balkans, for instance, while dominated by the Turks, the Austrians, and the Soviets. (And as soon as that region was not dominated by a foriegn power, the violence just started up again) First of all, would you agree that this is true and secondly would you say that the "rule with an iron fist" method is the method these empires took, and is it the only method to quiet a region that would otherwise engage in destructive ethnic violence? (hopefully it is not), And if so, Americans don't fancy being the type to provide an "iron fist," so what follws from there?
Personally, if I had been president after 9/11, my first priority would be to do the grand strategic equivalent of achieving full freedom of action. Do everything possible to become energy-independent. (Placing worries about where the money paid for oil ends up aside) The US need for oil compels it to act in certain specific ways. The equivalent of a direct, frontal attack. Predictable and unalterable. It's the equivalent of not being able to maneuver. Making policy on a no-need-for-oil basis would open up all kinds of other possibilities... the US need not act on any of these, but at least it opens up the possibility with posing the enemy with a dillemma as opposed to letting them act on certain unalterable facts.
As for war with Iran.... somebody tell me how overly optimistic I am. (I'm using WW2 analogies because this is an area of military history I'm fairly familiar with) Wouldn't the US enjoy a combination of the operational superiority the Germans had over the Soviets when they could cut up Soviet formations even at 8:1 odds, combined with the air superiority enjoyed by the Allies during the invasion of France, where it took longer for German formations to get from the French border to Normandy than it did to get from the Eastern Front to the border of France due to all the Fighter-Bombers doing prescision attacks on traveling units and transportation infrastructure? I mean, wouldn't supplies for an invading Iranian army be limited to what they could carry in on their backs? Would there BE such things as roads or railways in Iran two weeks after a declaration of war or sneak attack? Wouldn't the US pull together whatever mechanized forces they had in the theatre of war and cut up the Iranian formations in conjunction with air power? I just can't see how Iran could keep their forces concentrated if supplying them becomes impossible and keeping them concentrated would create good targets for the air force. I'm fairly well-read on military history and strategy for a layman, but that's about it. I'd be interested in anyone's realistic informed take on how a US-Iran war started by Iran would go.
