In public school disputes, arbitrators will be faced with challenges to the arbitrability of a wide range of subjects. The challenger will assert that, despite the fact that the parties have a contractual provision on the subject, the subject was not a proper one for bargaining, as it falls within the exclusive prerogative of the school board. “It seems to me that the better part of wisdom under these circumstances is for the arbitrator to confine himself/herself to the contract and not attempt any reconciliation between external law and the contract.”