The unrest in Sudan next door (over an international arrest warrant being issued for the Sudanese president) has led to foreign aid workers being thrown out of Sudan. This means a lot, if not most, of the food and medical aid is no longer coming in. The aid groups in Chad fear that hundreds of thousands of hungry Darfur refugees could try to cross the border to reach the eastern Chad refugee camps. There would not be enough food and water in these camps to handle a large number of new refugees from Darfur.
In influx of more refugees would bring with it more crime and banditry. Already, aid groups are suffering 20-30 attacks on their personnel or resources a month. Most of this is just robbery, as the bandits know that kidnapping will bring lots of heat down on them. However, if the half million refugees in eastern Chad found themselves dealing with another few hundred thousand from Darfur, the lawless behavior by the criminals who would accompany the move, would overwhelm the ability of the peacekeepers to prevent kidnappings or large scale raids on camps or the refugees themselves. There are now 5,000 UN peacekeepers in Chad, who must keep an eye on the situation in the southeast, where a thousand refugees a week are fleeing civil war in neighboring Central African Republic (CAR).
March 15, 2009: The UN took control of the peacekeeping operation in Chad. Some two-thirds of the EU troops will remain, and become UN peacekeepers. The EU troops will stay for a few months, or longer if the situation gets a lot worse.