Doctrine of fair comment

Borjal v. Court of Appeals (G.R. No. 126466, January 14, 1999) confirms the teaching regarding the doctrine of fair comment.
To reiterate, fair commentaries on matters of public interest are privileged and constitute a valid defense in an action for libel or slander. The doctrine of fair comment means that while in general every discreditable imputation publicly made is deemed false, because every man is presumed innocent until his guilt is judicially proved, and every false imputation is deemed malicious, nevertheless, when the discreditable imputation is directed against a public person in his public capacity, it is not necessarily actionable. In order that such discreditable imputation to a public official may be actionable, it must either be a false allegation of fact or a comment based on a false supposition. If the comment is an expression of opinion, based on established facts, then it is immaterial that the opinion happens to be mistaken, as long as it might reasonably be inferred from the facts.
The doctrine of fair commentaries requires that the comment must NOT be based on false supposition. (G.R. No. 170721, Aug. 23, 2017)