As troops from other nations begin to relieve American and British forces, a major problem is developing. US and British troops have the best civil affairs (working with civilians in wartime) capability in the world. The US Army has maintained a large force of civil affairs troops since World War II. The marines literally wrote the book (the Small Wars Manual) on these kinds of operations and have long been noted for their skill and enterprise in working with civilians. Many of the new troops coming in have experience with United Nations peacekeeping operations. Unfortunately, the UN operations are usually rife with corruption and mismanagement. In many cases in Iraq, efficient American troops are being replaced by contingents less willing to work, and more eager to steal. This is going to lead to more unrest among civilians, and make it easier for the criminal gangs, Saddam diehards and Islamic radicals to operate.
American commanders are not unaware of these problems, but they have limited resources to deal with it. There are an increasing number of Iraqi police and para-military security forces being put to work, and these are supervised by Americans (usually civilians.) There are still US Army civil affairs troops to work with the foreign contingents, but the new peacekeeping troops cannot be watched full time. Moreover, the new peacekeepers will not patrol, or operate against Iraqi resistance, as effectively as American troops.
But the corruption will be the biggest problem. Iraq is already a very corrupt place to begin with. A "civil society" has yet to become widespread in Iraq. Most Iraqis look to their tribe or clan for justice. Everyone else is seen as either a temporary ally, or potential victim. Saddam Hussein turned the Baath Party into a new "tribe", which was capable of exploiting all the existing tribes and special interest groups (like the powerful Shia clergy). Saddam exploited the traditional tribalism to keep himself in power. Now, with the Baath Party no longer in charge, Iraqi politics has reverted to the ancient tribal and clan competition. For the past century, there have been a growing number of educated Iraqis active in trying to establish a Western style "civil society." But this would mean tribes would be superceded by fair courts and police who were not corrupt. The tribal leaders don't want to give up the power, and it's no easy task to create courts and police who cannot be easily bought or intimidated. Add to this volatile mix peacekeepers who can be compromised, and the situation will only get much worse.
So don't be surprised when the stories about corrupt peacekeepers in Iraq begin to appear. It's an old story, moved to a new location by the same cast of characters.