...And, much as President François Hollande of France denies that his country is still the gendarme of francophone Africa, the columns of French soldiers and planeloads of paratroops embroiled in the newest fighting recall much earlier campaigns.

“There was a time when General Faidherbe pursued armed bands attacking the forts of the Sahel, and even then they professed radical Islam,” Bertrand Badie, a political science scholar in Paris, wrote in Le Monde, referring to Gen. Louis Faidherbe, who played a central role in solidifying French interests in the broad swath of desert known as the Sahel in the 19th century. “What have we done since then?”

For many years, French military intervention in Africa functioned as the guardian of French economic interests and of the large expatriate French communities who benefited from them in cities like Libreville in Gabon and Abidjan in Ivory Coast. French troops defined the longevity of protégé African leaders. The French presence was a postcolonial bulwark, too, against British influence in southern and eastern Africa....