The United States is funding and in many cases arming the three ethnic factions in Iraq — the Kurds, the Shiites and the Sunni Arabs. These factions rule over partitioned patches of Iraqi territory and brutally purge rival ethnic groups from their midst. Iraq no longer exists as a unified state. It is a series of heavily armed fiefdoms run by thugs, gangs, militias, radical Islamists and warlords who are often paid wages of $300 a month by the U.S. military. Iraq is Yugoslavia before the storm. It is a caldron of weapons, lawlessness, hate and criminality that is destined to implode. And the current U.S. policy, born of desperation and defeat, means that when Iraq goes up, the U.S. military will have to scurry like rats for cover.

The supporters of the war, from the Bush White House to Sen. John McCain, tout the surge as the magic solution. But the surge, which primarily deployed 30,000 troops in and around Baghdad, did little to thwart the sectarian violence. The decline in attacks began only when we bought off the Sunni Arabs. U.S. commanders in the bleak fall of 2006 had little choice. It was that or defeat. The steady rise in U.S. casualties, the massive car bombs that tore apart city squares in Baghdad and left hundreds dead, the brutal ethnic cleansing that was creating independent ethnic enclaves beyond our control throughout Iraq, the death squads that carried out mass executions and a central government that was as corrupt as it was impotent signaled catastrophic failure.

The United States cut a deal with its Sunni Arab enemies. It would pay the former insurgents. It would allow them to arm and form military units and give them control of their ethnic enclaves. The Sunni Arabs, in exchange, would halt attacks on U.S. troops. The Sunni Arabs agreed.

The U.S. is currently spending hundreds of millions of dollars to pay the monthly salaries of some 600,000 armed fighters in the three rival ethnic camps in Iraq. These fighters — Shiite, Kurd and Sunni Arab — are not only antagonistic but deeply unreliable allies. The Sunni Arab militias have replaced central government officials, including police, and taken over local administration and security in the pockets of Iraq under their control. They have no loyalty outside of their own ethnic community. Once the money runs out, or once they feel strong enough to make a thrust for power, the civil war in Iraq will accelerate with deadly speed. The tactic of money-for-peace failed in Afghanistan. The U.S. doled out funds and weapons to tribal groups in Afghanistan to buy their loyalty, but when the payments and weapons shipments ceased, the tribal groups headed back into the embrace of the Taliban.

The Sunni Arab militias are known by a variety of names: the Iraqi Security Volunteers (ISVs), neighborhood watch groups, Concerned Local Citizens, Critical Infrastructure Security. The militias call themselves “sahwas” (“sahwa” being the Arabic word for awakening). There are now 80,000 militia fighters, nearly all Sunni Arabs, paid by the United States to control their squalid patches of Iraq. They are expected to reach 100,000. The Sunni Arab militias have more fighters under arms than the Shiite Mahdi Army and are about half the size of the feeble Iraqi army. The Sunni Awakening groups, which fly a yellow satin flag, are forming a political party.

The Sunni Arab militias, though they have ended attacks on U.S. forces, detest the Shiite-Kurdish government of Prime Minister Nouri al-Maliki and abhor the presence of U.S. troops on Iraqi soil. They take the money and the support with clenched teeth because with it they are able to build a renegade Sunni army, a third force inside Iraq, which they believe will make it possible to overthrow the central government. The Sunni Arabs, who make up about 40 percent of Iraq’s population, held most positions of power under Saddam Hussein. They dominated Iraq’s old officer corps. They made up its elite units, including the Republic Guard divisions and the Special Forces regiments. They controlled the intelligence agencies. There are several hundred thousand well-trained Sunni Arabs who lack only an organizational structure. We have now made the formation of this structure possible. These militias are the foundation for a deadlier insurgent force, one that will dwarf anything the United States faced in the past. The U.S. is arming, funding and equipping its own assassins.

There have been isolated clashes that point to a looming conflagration. A Shiite-dominated unit of the regular army in the late summer of 2007 attacked a strong Sunni Arab force west of Baghdad. U.S. troops thrust themselves between the two factions. The enraged Shiites, thwarted in their attack, kidnapped relatives of the commander of the Sunni Arab force, and American negotiators had to plead frantically for their release. There have been scattered incidents like this one throughout Iraq.

If the U.S. begins, as promised, to withdraw troops, it will be harder to keep these antagonistic factions apart. The cease-fire by the radical Shiite cleric Moqtada al-Sadr, extended a few days ago, could collapse. And if that happens, a civil war, unlike anything U.S. forces have experienced in Iraq, will begin. Such a conflagration, with the potential to draw in neighboring states and lead to the dismemberment of Iraq, would be the final chapter of the worst foreign policy blunder in American history.