Strategic lawsuits against public participation, (SLAPP) refers to litigation filed by a large corporation (or in some cases, a wealthy individual) to silence a less powerful critic by so severely burdening them with the cost of a legal defense that they abandon their criticism. The acronym was coined in the 1980s by University of Colorado professors Penelope Canan and George W. Pring.
The U.S. state of California has a statute, Code of Civil Procedure § 425.16, that is intended to prevent the misuse of litigation in SLAPP suits. About a dozen other states have followed California's example with similar statutes. These statutes usually create a special motion which a defendant can file at the outset of a lawsuit.
There is no direct equivalent in American federal law; the closest available remedy is the Noerr-Pennington doctrine in federal antitrust law. According to Canan and Pring, this situation is probably because of differences in pleading requirements between federal and state civil procedure.
However, the U.S. Court of Appeals for the Ninth Circuit has allowed California litigants to use their state's special motion in federal district courts located in California, in cases where the court is hearing at least one California state law claim through the doctrine of supplemental jurisdiction.
Critics of Scientology claim that the organization regularly files SLAPP lawsuits against its opponents, and that the practice was written into Scientology "scripture" by L. Ron Hubbard.
SLAPPs--Strategic Lawsuits Against Public Participation: Coming to a Controversy Near You (http://www.uow.edu.au/arts/sts/sbeder/SLAPPS.html) -- Australian article, includes history of SLAPPs
Canan and Pring define a SLAPP as being a civil court action which alleges that injury has been caused by the efforts of individuals or nongovernment organisations to influence government action on an issue of public interest or concern.
Another effect of the SLAPP is to distract the key antagonists from the main controversy and use up their money, time and energy in the courtroom, where the issues are not discussed.
SLAPPs can also shift the balance of power giving the firm filing the SLAPP suit the upper hand when they are losing in the political arena.
Generally, a "SLAPP" is a (1) civil complaint or counterclaim; (2) filed against individuals or organizations; (3) arising from their communications to government or speech on an issue of public interest or concern.
SLAPP filers frequently use lawsuits based on ordinary civil claims such as defamation, conspiracy, malicious prosecution, nuisance, interference with contract and/or economic advantage, as a means of transforming public debate into lawsuits.
The filing of a SLAPP also impedes resolution of the public matter at issue, by removing the parties from the public decision-making forum, where the both cause and resolution of the dispute can be determined, and placing them before a court, where only the alleged "effects" of the public controversy may be determined.