The doctrine provides that while as a general rule, every discreditable public imputation is false because every man is presumed innocent, thus every false imputation is deemed malicious, as an exception, when the discreditable imputation is directed against a public person in his public capacity, such is not necessarily actionable.

For it to be actionable, it must be shown that either there is a false allegation of fact or comment based on a false supposition. However, if the comment is an expression of opinion, based on established facts; it is immaterial whether the opinion happens to be mistaken, as long as it might reasonably be inferred from facts. (Borjal v. CA, G.R. No. 126466, Jan. 14, 1999)