But there is another threat that the Shias and Kurds can employ:
In Baghdad, meanwhile, Iraqi politicians praised a deal Monday among the largest Shiite, Sunni Arab and Kurdish groups that delays a possible division of Iraq until the constitution is amended.
But Iraq's second-largest Sunni group rejected the deal and promised to fight any effort to divide the country now or in the future.
Some Sunnis want to work within a democratic Iraq. Some Sunnis hope to bide their time within Iraq and prepare for a coup in a decade or two to regain power over the Shias and Kurds.
Both strategies require a unified Iraq.
So the Shia and Kurd threat to essentially split up Iraq is a major threat to Sunnis who want to cooperate and Sunnis who want to regain absolute power. Split up Iraq and the Shias will have the power to expel Sunnis from Baghdad and push them all into al Anbar province.
The Kurds in the north will have oil and the Shias in the south will have oil.
The Sunnis in Anbar will have sand, fleas, heat, and the joys of fanatical Sunni beliefs.
I personally do not think we can trust the Sunnis on their own even in a desolate wasteland. They may have buried nasties out west and Sunnis the world over would donate money to the Iraqi Sunnis to battle the hated Shias. We simply can't trust the Iraqi Sunnis to run their own affairs. They need a generation under a democratic Iraq as a minority to rejoin civil society.
I think the Shias are mostly bluffing and want a unified Iraq. But if the Sunnis won't play ball, the Shias will just stiff the Sunnis and let them go--and the Kurds will take advantage to go their own way.
A very high stakes game of chicken is going on, I think.