Analysis: Conflict in Chad has roots in Darfur
The Sudanese and Chadian governments have armed the rival militias and in doing so they have let the genie out the bottle. Now, even if they wanted to do so, it is unlikely they could get it back in. At the same time the Sudanese government has prevented the UN from establishing a credible force in the area.
The east of Chad and the Darfur region of western Sudan are effectively the same place - the border between them is arbitrary and the same tribes live on both sides. They have no allegiance to either country, only to their clans.
Why is Sudan accused of backing the rebels?
The Zagawa tribe, the tribe to which Chad's President Deby belongs, was one of the three main tribes involved in the fighting against the Sudanese Government in the early days of the Darfur conflict.
Now the Sudanese has started backing the anti-government rebels in Chad in retaliation. At best, they say that since coming to power in 1990 President Deby has turned a blind eye to anti-Sudan movements in Chad, at worst he supported them and fuelled the conflict.
What is the United Force for Change (FUC)?
The FUC consists of other eastern tribes opposed to the Zagawa tribe of the Chadian President. This is a part of the world which hasn't changed for centuries, so there is historic enmity dating back for centuries, making it an easy recruiting ground for rebels.
They are very keen on deposing President Deby before the election in May. They know perfectly well that he will win - if you are the incumbent you always win - and things will become even more entrenched. Since the President's army is not particularly effective, the militias, presumably with the help of the Sudanese army, have swept across Chad in rapid time to reach the capital.
What would happen if President Deby is overthrown?
It would be very much business as usual. In a way, things in Chad can't get much worse. It will be bad news for the refugees who fled Sudan, they will find themselves under a Government supported by the same figures from whom they initially fled. The major problem is that increased instability in the area would make the aid efforts that are underway even more difficult.
Will the West intervene?
The only joker in the pack is France. It does have quite a large military detachment in Chad and a couple of airstrips. The French may decide that they want to keep President Deby in power, but I don't imagine any other countries will get involved. President Deby is no hero but it maybe a question of "better the devil you know".