what is an operative fact doctrine?

To explain, the operative fact doctrine exhorts the recognition that
until the judiciary, in an appropriate case, declares the invalidity of a certain
legislative or executive act, such act is presumed constitutional and thus,
entitled to obedience and respect and should be properly enforced and
complied with. As explained in the recent case of Commissioner of Internal
Revenue v. San Roque Power Corporation/66 the doctrine merely "reflect[ s]
awareness that. precisely because the judiciary is the governmental organ
which has the final say on whether or not a legislative or executive measure
is valid, a period of time may have elapsed before it can exercise the power
of judicial review that may lead to a declaration of nullity. It would be to
deprive the law of its quality of fairness and justice then, if there be no
recognition of what had transpired prior to such adjudication."267 "In the
language of an American Supreme Court decision: 'The actual existence of a
statute, prior to such a determination [of unconstitutionality], is an operative
fact and may have consequences which cannot justly be ignored.