As far as Frederick W. Kagan and William Kristol being great military strategists: They are neither strategists, nor are they schooled in the operational art, nor are they tacticians, nor are they generals, nor are they soldiers. Other than that, they are great military men.
Does anyone still take these idiots seriously? The next time they're right (at least about what's best for the United States, as opposed to best for Israel) will be the first time.
As a coherent nation-state of the Westphalian variety (territorial integrity, national sovereignty, etc.), Iraq was doomed from the moment Winston Churchill scratched out its borders on a cocktail napkin at the Cairo Conference.
It's the kind of cockeyed expedient that can only be held together, and then even then tenuously and at great cost in human freedom and human lives, by an extraordinarily violent authoritarian regime like that of Saddam Hussein's Arab Ba'ath Socialist Party.
The Kurds in the north want autonomy (and, ideally, a Kurdistan that spills over Churchill's borders into Syria, Turkey and Iran).
The Shiites in southern and central Iraq tend to identify with, and will almost certainly eventually become part of a Greater, Iran.
At the time of Iraq's creation, TE Lawrence's "Arab Awakening" was all the rage among westerners who had no idea what they had unleashed. Saudi-backed Sunni fundamentalists and Ba'athist/Nasserite "Arab nationalists" are both products of that madness. It's hard to say which one is worse, but obviously the US government should have thought harder before un-horsing the latter and leaving the field open to the former.
The quicker the US lets Iraq start sorting out its own problems, the quicker those problems will cease to be American problems and the less traumatic the residual blowback will be.
If advocacy has consequences, Kagan and Kristol already have the blood of untold thousands -- Americans and Iraqis among others -- on their hands. To continue taking their advice would conform strongly to any reasonable definition of insanity.
[Cross-posted at Come Home America]