A California law that protects workers from discrimination regardless of immigration status could be used by a migrant to sue his employer even though he used another man’s Social Security number, the state Supreme Court ruled on Thursday. The 5-2 decision by the court came in the case of a man who sued his former employer, Sierra Chemical Co., contending he was not brought back for seasonal work in retaliation for filing a worker’s compensation claim. Justice Joyce Kennard, writing for the majority, cited a 2002 California law intended to grant unauthorized immigrants the same protections as other workers.