SLAPP stands for "Strategic Lawsuit Against Public Participation." The name arose in the early 1990s, in response to a trend that many people found very disturbing. Large corporations, or individuals with a lot of power and money, would sue their critics for defamation, even though it would be quite obvious that they have little chance of winning, because their critics were speaking about matters of public concern.
How Are Speakers Protected Against SLAPPs?
Obviously, the fact that deep-pocketed entities were using the courts to stifle the free-speech rights of their critics was cause for significant concern. For that reason, several states have passed laws designed to protect individuals and non-profit organizations from these lawsuits.
These laws, known as "Anti-SLAPP Laws", allow defendants in these lawsuits to have the cases dismissed very early in the proceedings, and to recover attorney's fees, through what's known as an Anti-SLAPP motion. In order to prevail on such a motion, the defendant has to show that the statement the plaintiff is suing over concerns a "public issue." This can be virtually any topic that might be of concern to the public. Once this is established, the burden shifts to the plaintiff to show that it is likely to win its lawsuit on the merits, usually through a showing that the statements it complains of are clearly untrue, and made with knowledge of that fact.
If the plaintiff cannot show that it is likely to win on the merits, the lawsuit is dismissed, and the defendant is usually awarded their attorney's fees and costs they incurred in defending the suit. However, if the plaintiff shows that they are likely to win on the merits, the lawsuit is allowed to proceed. However, the fact that the court earlier determined that they were likely to win on the merits cannot be used in any way when the jury has to decide the merits of the case. A plaintiff who successfully defeats an Anti-SLAPP motion usually can't collect attorney's fees unless they can show that the motion was frivolous.
Approximately half of the states in the U.S. have Anti-SLAPP laws. They vary widely in the degree of protection they provide, but the laws of California and Oregon are generally seen as being the most protective of speakers.
If you are being sued for defamation, and believe that your speech is protected by the First Amendment to the U.S. Constitution, or the equivalent free speech protection in your state constitution, a government attorney specializing in libel or slander defense, or free speech law, will be able to advise you about the protections provided by the laws of your state, and will be able to file an Anti-SLAPP motion, giving you a good chance of getting the lawsuit dismissed.