Decision 8 G.R. No. 221139 The first situation demands a concurrence between a clear legal right accruing to petitioner and a correlative duty incumbent upon respondents to perform an act, this duty being imposed upon them by law. Petitioner's legal right must have already been clearly established. It cannot be a prospective entitlement that is yet to be settled. In Lim Tay v. Court of Appeals, this Court emphasized that "[m]andamus will not issue to establish a right, but only to enforce one that is already established." In Pefianco v. Moral, this Court underscored that a writ of mandamus "never issues in doubtful cases." Respondents must also be shown to have actually neglected to perform the act mandated by law. Clear in the text of Rule 65, Section 3 is the requirement that respondents "unlawfully neglect" the performance of a duty. The mere existence of a legally mandated duty or the pendency of its performance does not suffice. The duty subject of mandamus must be ministerial rather than discretionary. A court cannot subvert legally vested authority for a body or officer to exercise discretion. In Sy Ha v. Galang: [M]andamus will not issue to control the exercise of discretion of a public officer where the law imposes upon him the duty to exercise his judgment in reference to any matter in which he is required to act, because it is his judgment that is to be exercised and not that of the court. This Court distinguished discretionary functions from ministerial duties, and related the exercise of discretion to judicial and quasi-judicial powers. In Samson v. Barrios: Discretion, when applied to public functionaries, means a power or right conferred upon them by law of acting officially, under certain circumstances, according to the dictates of their own judgments and consciences, uncontrolled by the judgments or consciences of others. A purely ministerial act or duty, in contradistinction to a discretional act, is one which an officer or tribunal performs in a given state of facts, in a prescribed manner, in obedience to the mandate of legal authority, without regard to or the exercise of his own judgment, upon thi~ propriety or impropriety of the act done. If the law imposes a duty upon a public officer, and gives him the right to decide how or when the duty shall be performed, such duty is discretionary and not ministerial. The duty is ministerial only when the discharge of the same requires neither the exercise of official discretion nor judgment. ... Mandamus will not lie to control the exercise of discretion of an inferior tribunal ... , when the act complained of is either judicial or quasi-judicial. ... It is the proper remedy when the case presented is outside of the exercise of judicial discretion. 40 (Emphasis in the original, citations omitted) 40 Id. at 7-8. !