When U.S. troops were ambushed in Niger on Oct. 4, the widespread reaction was surprise. The U.S. has military forces in Niger? What are they doing there?
Yet in many ways, the Niger operation typifies U.S. military missions underway in roughly 20 African countries, mostly in the northern third of the continent. They tend to be small, they are carried out largely below the radar, and most are focused on a specific aim: rolling back Islamist extremism.