JOSH, a young social-studies teacher working in a tough part of Los Angeles, had been on the job for less than a year when word came that it might not last much longer. Its public finances in ruins, California was slashing budgets and laying off thousands of teachers. Josh’s headmaster fought to keep him, but his hands were tied; under the state’s strict “last in, first out” seniority rules, enshrined in statute, the most recent recruits had to be fired first, regardless of ability.

