The New Jersey Supreme Court ruled Monday that a state arbitrator in a school employee tenure case has the authority to impose their own penalty — a decision that sent a West New York assistant principal back to the classroom. The 19-page unanimous ruling overturned an appellate panel decision that stated an arbitrator in the case of Amada Sanjuan, an assistant principal at Memorial High School, could only decide whether she be fired or instead suffer a loss of salary, the disciplinary measures recommended by the state Department of Education (DOE). The school board certified tenure charges ag…