New analysis by the International Crisis Group. In my opinion, they usually either state the obvious too late or give a general worst-case scenario. I think the latter is applied here.
Will Sudan break up? This is a near certainly.
Will that break up happen violently? Yes and no.
Yes, the northern security apparatus will fight to hold onto northern oil areas and Darfur. I dont believe they can fight effectively to hold on to the south. They dont have the depth of power projection required to do it effectively. That's not to say they cant or wont try -- they are notorious for making bad decisions and choosing the worst path given any choice. It's a gamble they might not be willing to risk; war on the south and in Darfur would require a security presence to guard Khartoum that they cant afford.