Now we know. Baath leaders have sufficient cash to pay unemployed soldiers and secret policemen to attack American and Iraqis working for the coalition or transitional government. The solution for that is actually quite simple, and right out of the "Small Wars Manual" the Marine Corps wrote in the 1930s. First, you help rebuild the country. In 80 percent of Iraq, the only contact Iraqis have with coalition troops is watching them, or working with them, on reconstruction projects. In the Sunni Arab areas there are a couple of dozen incidents a day. More than half of them are attacks on Iraqis. As a result of this, about a third of the U.S. troops in Iraq are suffering about 90 percent of the casualties. The "Sunni Triangle" is something of a battlefield, but in ways most outsiders don't appreciate. For one thing, there is much factionalism (especially that based on tribes) in Iraq, and this is true among the Sunni Arabs as well. Iraqis spend more time shooting at each other than they do at Americans. There's a good reason for this, as when the American troops shoot back they usually hit what they are shooting at. So Baath gunmen prefer to attack other Iraqis. Most of the Iraqi attacks with assault rifles and RPGs against Americans are ineffective, and bombs are becoming more popular, While the remote control bombs have been quite effective, they have also killed and injured lots of Iraqis. Rewards have been offered for information on those bombs, and Iraqis have been cashing in by providing tips on who and where.
Over the next year or two, the Sunni Arabs will find themselves facing more Iraqi police and soldiers. Some of these will be Sunni Arabs, as many Sunnis didn't care to be run by a gang of corrupt tyrants, even if they were Sunni Arabs. But it will eventually come down to a civil war type of situation. Millions of Sunni Arab Iraqis are willing to support Baath and resist. It will take years of unrest before the last Baath diehard puts down his gun, or is shot dead.
Meanwhile you have corruption, tribalism and a lousy work ethic to deal with. The latter is the result of Baath running the country as a private fiefdom for the last three decades. Bit by bit, most entrepreneurs were eliminated and most businesses became state owned or controlled. Party loyalty was more important that workplace efficiency. For most Iraqis, like citizens of communist countries after the Soviet Union collapsed, delivering a day's work for a day's pay is a somewhat alien concept. The endemic corruption doesn't help either. Iraqi contractors will often look for a way to make it appear that the job was done rather than actually do it. Their idea of efficiency is looking for the right person to bribe as quickly as possible. What doesn't work in Iraq (both before Baath, during Baath and now) can often be traced to the corruption.
The tribalism is a special problem that at least has a positive side. The tribes have been around for thousands of years and their organization has survived as a means to provide some degree of justice and a social security net for people. But many tribes operate like criminal gangs and some tribes, to American eyes, ARE criminal gangs. Leadership in a tribe is not hereditary, but goes to a small number of families that keep producing the most capable leaders. Usually aided by a council of elders (senior members of other powerful families), the tribal chiefs wield great power and influence. No elected (or unelected) leader of Iraq can ignore the tribal leaders.
So a principal objective of the coalition occupation is to get the majority of Iraqis organized well enough to hold an election, and then carry on fighting the Baath Party by themselves.
About a third of the American troops in Iraq are taking nearly all the casualties. These are the troops who work in the "Sunni Triangle" and are fighting Baath Party diehards. The "Sunni Triangle" area in and outside of Baghdad is occupied by Sunni Arabs who supported (and many still support) Saddam Hussein, formed the core of the Baath Party and have tyrannized the Kurds and Shia Arabs for centuries. The Sunnis don't necessarily want Saddam back, but they do want to be back in charge of the country. Since so many of them belonged to the Baath Party, or worked for the Republican Guard and secret police, there is high unemployment. The Sunnis had it so good for so long that many have never had to really work for a living. Unless you call terrorizing, torturing and murdering non-Sunni Arabs "work." The coalition knew going in that the Sunni Arabs might continue to resist. The Sunnis had been in charge (even when the Turks and British were occupying Iraq) for centuries and no one quite knew how Baath would react to being out of power.