Iraq isn't slipping into Civil War, it's never emerged from the civil disorder that arose when Saddam's police state was taken apart three years ago. Five decades of Sunni Arab dictatorship, and three decades of Saddam's increasingly murderous police state, had changed Iraqi society. The change was similar to what was discovered when the communist governments of Eastern Europe were overthrown in 1989-91. People were glad to be free, but still cursed with many bad habits acquired during decades of despotic rule. One of the worst habits was an unfamiliarity with how law and order works, and why it's so important. All of these former communist governments had to deal with outbreaks of disorder once they became democratic. It's worse in Iraq, because Saddam's police state was one of the most savage ever known (matched only by the one still in power in North Korea). Saddam's supporters, drawn largely from his own Sunni Arab community, still believe Sunni Arabs should be running Iraq. The more religious among them believe Sunni Arabs should be running the world (one of al Qaeda's goals). But it isn't just the old villains who fight on, but some new ones as well. The Shia Arabs, who for so long were brutally suppressed by the Sunni Arabs, are now split into several factions. Some of these groups have lots of support from the Iranian government, who want a Shia religious dictatorship established in Iraq. American intelligence is picking up evidence of increasing Iranian efforts to make this happen. It's not likely to happen simply because most Iraqis (including most Iraqi Shia Arabs) oppose it. But the Iranian government is run by Islamic radicals, who have lots of money, and believe they are on a mission from God.
So what is the Iraqi government to do with this mess? Actually, the situation is typical of the region, where memories are long, factions are many and tempers are short. You make deals with as many factions as you can, and kill or imprison those who refuse to negotiate. Doing this in a democracy is also not unknown in the region (but it is very rare), and it means more attention being paid to what the voters think. A free press further complicates the situation. Most Iraqis, however, just want peace and prosperity. Neither is likely to happen until the manic guys with guns are put out of business. Most Iraqis appear to accept this solution, as all the others have been tried and failed.
There are already some 250,000 Iraqi security personnel armed and at work. Another 60,000 or so will be in action by the end of the year. To that end, American troops are starting to pack up for the return home. In any military operation, logistics takes precedence over everything else. In Iraq, there's a huge logistical operation under way to identify which equipment will be shipped home first, and which will be given to the Iraqi armed forces. Many American bases have already been transferred to the Iraqis, and thousands of U.S. troops back home have been told their movement to Iraq has been delayed, perhaps indefinitely.