DEFENCES
Even if a statement is derogatory, there are circumstances in which such statements are permissible in law.
Truth
In many legal systems, adverse public statements about legal citizens presented as fact must be proven false to be defamatory or slanderous/libel. Proving adverse, public character statements to be true is often the best defense against a prosecution for libel and/or defamation. Statements of opinion that cannot be proven true or false will likely need to apply some other kind of defense. The use of the defense of justification has dangers, however; if the defendant libels the plaintiff and then runs the defense of truth and fails, he may be said to have aggravated the harm.
Another important aspect of defamation is the difference between fact and opinion. Statements made as "facts" are frequently actionable defamation. Statements of opinion or pure opinion are not actionable. In order to win damages in a libel case, the plaintiff must first show that the statements were "statements of fact or mixed statements of opinion and fact" and second that these statements were false. Conversely, a typical defense to defamation is that the statements are opinion. One of the major tests to distinguish whether a statement is fact or opinion is whether the statement can be proved true or false in a court of law. If the statement can be proved true or false, then, on that basis, the case will be heard by a jury to determine whether it is true or false. If the statement cannot be proved true or false, the court may dismiss the libel case without it ever going to a jury to find facts in the case.
In some systems, however, notably the Philippines, truth alone is not a defense. Some U.S. statutes preserve historical common law exceptions to the defense of truth to libel actions. These exceptions were for statements "tending to blacken the memory of one who is dead" or "expose the natural defects of one who is alive."
It is also necessary in these cases to show that there is a well-founded public interest in the specific information being widely known, and this may be the case even for public figures. Public interest is generally not "that which the public is interested in," but rather that which is in the interest of the public.