I thought that when the US embarked upon the fools mission of invasion of Iraq with it's built in three-way ethnic/religious divide, that they should have split

I thought that when the US embarked upon the fools mission of invasion of Iraq with it's built in three-way ethnic/religious divide, that they should have split the state three ways, but barring that, they should have done some sort of find-grained grid of local control. Then, after a year or two, examined each as to how they allocated their reconstruction funds and established a functioning civil government. After two years, and if a grid "square" (doesn't HAVE to be a grid) is being heavily mismanaged, you pick one of the surrounding grids and pick the one with the best functioning civil governance, and give them control over THAT grid. But far too late for that. Trillions of dollars evaporated. Of course our best potential ally, the Kurds, we didn't support enough. God we are so stupid.