Should we just divide Iraq into 3 territories?

The only factions that we hear about being a part of the insurgency is Shiites and Sunni's but there is a third faction, the Kurds. According to our own military, the secterian violence has diminished mostly because these factions have 'segregated' themselves by ethnic cleaning. Why not just take the land and divide it amongst the factions, giving the land that borders Iran and Syria to the Shiite, the land that borders Saudi Arabia to the Sunni's and the border towards Turkey to the Kurds???