GABORONE, June 10 -- Motshwegwa Rakhudu spent fourteen years installing equipment in the diamond mines that made his country rich, on the kind of rolling contract that everyone treated as permanent. He expected the work to carry him to 2027. Instead it ended without warning, and the shock, he said, was too much. He is one face of a reckoning that an entire nation built on a single stone is now being forced to have.

For Rakhudu the math is brutal and small. Jobs are scarce, he said, and the work that does exist outside mining pays far less; he would move into farming, but selling his car would only clear the loan on it. Multiply that arithmetic across thousands of households and it becomes a national condition. The diamond downturn, as Mb...