Fighting in the Sahel has forced 1.7m people from their homes

WESTERN GOVERNMENTS have long debated whether the costs of intervening in dangerous parts of the world exceed the risks. In February the United States signed a peace deal with the Taliban in Afghanistan. But just as America extricates itself from one conflict, a power vacuum in Africa’s Sahel may drag it into another.

The Sahel, a semi-arid strip south of the Sahara desert spanning 4,000 miles (6,400km), is unusually troubled. Its hinterlands are far from any city and mainly populated by nomads. The state’s writ does not hold; public services barely exist. The Sahel’s borderlands have long been dangerous: just 3.5% of the population of north and west Africa lives within 10km of an international frontier, but 10% of deaths from armed violence occurred in these areas between 1997 and 2019.