Well, this is a wrinkle – nature abhors a vacuum.
Sudan is in the middle of a civil war that has claimed 300,000 lives. The Northern part of Sudan is controlled by Arabs and the south be black Africans. North Sudan has some oil reserves in the same general area as their border area with Libya.
So is Sudan there to help Qadaffi? Working with the rebels? Protecting refugees? Invading?
Destroying the Libyan military has consequences. Qaddafi has said Europe should prepare for a plague of locusts. In the 1980s, the Reagsn administration urged Chad (next door) to push Libyan troops out of their border area. The Rebels have made it pretty clear they think all black Africans want them dead. Bengazi is not protecting its flanks from attack.