http://www.amazon.com/Art-Wargaming-Guide-Professionals-Hobbyists/dp/0870210505

Much of the above discussion focused on mistakes made during the interwar period but little has been said about the successes. Many of these successes stemmed from the thinking, studying, and wargaming of the U.S. Navy, particularly at the Naval War College in Newport, RI. By drawing on the power of wargaming to elicit thoughtful competition and to expose ideas and theories to ruthless attack on the game board, the U.S. Navy devised much of the ultimate operational approach that helped win the war in the Pacific.

Admiral Nimitz wrote a famous post-war letter praising the wargmaing done there as helping the Navy foresee and at least think about everything that they faced during the war, except the kamikaze. That might be a tad overstated, but his comments are certainly valid. Like any tool, of course, wargaming can be mis-used and itw surely was by many of the participants in WWII. Just as the wargaming done in preparation for the 2003 Iraq war raised important issues that decision makers chose not to address, the key is not simply to game things out, but to incorporate insights and ideas derived from gaming with those from analysis, military exrecises, and real-world experience. That's the closest thing to a military crystal ball we are likely to find outside the world of Harry Potter. But it still requires thoughtful and resolute professionals to take the right lessons and make the right decisions.

Also a lot of the planning is politically driven – what can I sell to the politicains (who are the ones supplying the money)?

For example, the US armor community prior to WW II was divided between those who argued that tanks should ONLY be used as infantry support, and those that demanded full autonomy for tanks. They were both wrong. Combined arms advocates had existed, but the politics of the Army of the 1920s and 30s had smothered them.

The tank destroyer concept was based upon the VERY biased opinions of one COL Fuqua, the US attache to the Spanish Civil War. Fuqua was an infantryman, and let his prejudices show through in his reports which helped turn US thinking to tank destroyers. The only way TDs were 'proved' during manuevers was when the AGF changed the rules to overstate the effectiveness of AT weapons to the point that a soldier with a bag of flour (grenade) could knock out a tank.

More recently, the US in Iraq had the historical experience to fight an insurgency, but the biases of the higher echelons refused to admit what was going on, thereby creating a larger issue. In 2003 we weren't even supposed to use the word 'insurgent'.

Bottom line – preparing to fight the last war is really looking at history, and making preparations. This is good solid sense and really is the reason to study military history (those who don't study history are bound to repeat it, etc.). However, nations and militaries that do the worst job of dispassionately viewing "WHAT ACTUALLY HAPPENED" and WHY are those that end up doing the worst.