From what I've read and seen recently, North is not alone among erstwhile Bush supporters in his skepticism. It's a wonder that the relatively large proportion of skeptics with some military competency isn't making any impression at all on Bush. You can't paste a smiley face on the fact that the two top generals who disagreed with "surge" as a euphemism for "escalation" were fired-by-promotion.

The way I see it, the fact that while the Iraqi army was organized along Soviet-style lines may have made them an unsuitable instrument for us at the start, disbanding it represents a terrible wasted opportunity. While it was badly-trained, it was massively organized, and we could have taken it over whole and complete by inserting our own commanders into that rigid chain of command. They could have then simply have ordered the troops to retrain, producing soldiers more suitable for our purposes and whose obedience, if not loyalty, would have seamless transferred to the new regime.

The discontinuity we introduced by summarily disbanding them and telling them to fend for themselves is proving to be almost impossible to overcome. It's impossible to identify "the" fatal mistake among so many terrible mistakes that have produced the present mess, but that one is surely a huge contributor.