In Greene County v. District 2, United Mine Workers of America, 578 Pa. 347, 852 A.2d 299 (2004), our supreme court explained the rationale behind the core function test, stating Unlike private sector employers, public employers are ultimately responsible for the health, safety and welfare of our communities. Due to their unique nature and role, public employers must be able to perform the functions they are charged to carry out by our citizenry. Consistent with this status, our Court has recognized that public employers cannot be compelled in arbitration to relinquish powers that are essential to the proper discharge of their functions. Thus, while as a general proposition, an arbitrator has broad authority to interpret an undefined provision regarding termination for just cause in a collective bargaining agreement, to permit an arbitrator to interpret the agreement as to require reinstatement of an employee who was determined to have engaged in egregious misconduct that strikes at the very core function of the public enterprise would be to deprive the employer of its ability to discharge that essential function. An arbitrator's award granting reinstatement in such a situation would not be rational and would therefore fail the essence test. Id., 578 Pa. at 362, 852 A.2d at 308.