Explaining the rebel attack on Khartoum

Alex De Waal attempts to make sense of Khalil Ibrahim's decision to send his Justice and Equality Movement into an attack on Khartoum:

As more details emerge about JEM’s assault on the national capital at the weekend, it is becoming clear that this was a solo operation by JEM directed by its leader Khalil Ibrahim. Its aim was nothing less than taking power.
...
Did Khalil truly believe that he could capture the national capital with a force of about 3,000 men? Taking into account Khalil’s own words after the attack, the answer seems to be yes.

According to De Waal, Khalil was acting primarily of his own initiative. Chadian President Deby has backed him in the past, but didn't think this attack was a good idea, and is now irate (though others in the Chad regime may have backed Khalil). Factions of the other main Darfur rebel grouping, the Sudan Liberation Army, were not involved in organizing the attack. Islamist opposition leader Hassan al-Turabi was pals with Khalil back in the day, but not anymore. Basically, Khalil is "arrogant, propelled by self-belief, and convinced that his cause will win through." So far, he's been pretty successful. We'll see if he's overreached this time.

Meanwhile, Andrew Heavens provides a more humble explanation of the attack:

So, after hours of exhaustive interviews, in depth research and the refining of my own expert analysis, I have at last come up with the motive behind JEM's shock attack on Khartoum.

It is any one of the following 10 explanations.