"They have an uphill battle. They need to fight back this coalition of Islamic groups, and then, 'What then?' " she says.
The Economic Community of West African States has not yet reached a consensus on how to deploy African forces to support the mission, which was supposed to begin later this year.
Newly elected French President Francois Hollande said in a press conference Tuesday that troops would remain in Mali until the country is safe and stable, though the French foreign minister said the engagement would only last for a matter of weeks.
Public support in France remains high for the mission. Almost two-thirds of the country support it, according to a Monday poll by the French Institute of Public Opinion, reported by the Christian Science Monitor.
But Roach questions how long that will stand, particularly if French troops start taking casualties.
The best case scenario involves a long, two-pronged approach, she says, of fighting off the Islamic militants as they hide among civilians, and push them back to arid, sparsely populated northern Mali.
A successful military campaign would have to be followed by resurrecting the Malian government to a state where it can defend itself.
This is an optimistic appraisal versus the worst outcome, of the French and Malians losing control of Bamako to the rebel fighters and Mali becomes under de facto Islamic extremist control.
The most likely situation, says Roach, is a combination of the two. Most of the fighters will be pushed back into the north, but some will remain blended in the civilian population. They won't be able to advance, but they also can't be pushed back.
It could lead to an eventual stalemate, she says. "I don't think this is going anywhere any time soon. The troops are very well dug in and for now, at least, they are unified and working together."