53 Pa. C.S. § 1132
Because of the existing possibility of attack upon the United States of unprecedented size and destructiveness and in order, in the event of such an attack, to assure continuity of government through legally constituted authority and responsibility in offices of the municipalities of this Commonwealth, to provide for the effective operation of government during an emergency and to facilitate the early resumption of functions temporarily suspended, it is found and declared to be necessary to provide for emergency interim succession to offices of the municipalities of this Commonwealth in the event the incumbents and their deputies authorized to exercise all of the powers and discharge the duties of these offices, referred to in this subchapter as deputies, are unavailable to exercise the powers and perform the duties of these offices.
53 Pa.C.S. § 1132