Negotiate a divorce, not a marriage?

Geoffrey Alderman in the Jewish Chronicle:

I agree with the Blair and Bush bashers that Iraq is a mess. This is not because of the presence of American and British troops. It is because Iraq is an artificial entity that was held together only through Saddam’s terror machine, torture chambers and poison gas. Once these instruments of oppression were removed, the artificial entity that we call Iraq was as bound to fall apart as was the Soviet Union once the forces of democracy reared their unsettling heads.
The entity we call Iraq was invented in the Colonial Office, in Whitehall, after the First World War. Its present borders were drawn up by clerks with rulers and set-squares. The Kurds, who had been brutally treated by the Ottoman Empire, ought to have been given their independence. Instead, they were compelled by Britain and France to join with various Sunni and Shi’ite tribes to form a completely artificial country over which Faisal, son of Hussein, guardian of the holy places of Mecca and Medina, who had fought alongside Lawrence of Arabia against the Ottomans, was set as ruler.
I can see little useful purpose in perpetuating this artificial creation. Perhaps it should be allowed to revert to the constituent but distinct ethnic groups compelled to submerge their identities within it almost a century ago.

This is not a new idea, however it is one that, as soon as Saddam was toppled, was dismissed out of hand by most people who perceived it to be too difficult to implement, mainly because the main population groups (sunni, shiite, kurds) do not live in completely separate geographical areas; because the sunnis don't want to be left in the most resource-poor area of the country on their own; the Turks don't want a Kurdish state; fear of Iranian interference in a shi'ite state, etc. We haven't heard much of it since then.
In just 2 weeks, the Iraqis are going to the polls to ratify their new, barely agreed upon constitution. The Sunnis have already said they are going to vote against en masse, so even if the constitution does pass, stability will probably not be restored, the insurgency is unlikely to quieten, and Iraq will still not be functioning comfortably as a whole.
Under such circumstances, when one option has been tried, tried, tried, tried and tried again, without success, perhaps a completely fresh approach is necessary -- a complete rethink, out of the box? It is clear that these people simply do not want to live with each other. Why not at least explore the option of letting them go their separate ways?
All the old objections still hold true, and there's no question that working out how to split up might be almost as difficult as trying to work out how to live together (and will not mean a quick exit from Iraq for US/British troops). That doesn't mean it can't be done, however -- and depending on the results and aftermath of the constitution referendum, perhaps it should be considered?