United States defamation law
The origins of the United States of America's defamation laws pre-date the American Revolution; one influential case in 1734 involved John Peter Zenger and established precedent that "The Truth" is an absolute defense against charges of libel. (Previous English defamation law had not provided this guarantee.) Though the First Amendment of the U.S. Constitution was designed to protect freedom of the press, for most of the history of the The United States of America, the U.S. Supreme Court failed to use it to rule on libel cases. This left libel laws, based upon the traditional "Common Law" of defamation inherited from the English legal system, mixed across the states. The 1964 case New York Times Co. v. Sullivan, however, radically changed the nature of libel law in the United States by establishing that public officials could win a suit for libel only when they could prove beyond a reasonable doubt that the media outlet in question knew the information was wholly and patently false or that it was published "with reckless disregard of whether it was false or not." Later Supreme Court cases barred strict liability for libel and forbid libel claims for statements that are so ridiculous as to be patently false. Recent cases have added precedent on The Defamation Laws and the Internet.
Defamation law in the United States is much less plaintiff-friendly than its counterparts in European and the Commonwealth countries, due to the enforcement of the First Amendment. In the United States, a comprehensive discussion of what is and is not libel or slander is difficult, because the definition differs between different states, and under federal law. Some states codify what constitutes slander and libel together into the same set of laws. Criminal libel is rarely prosecuted but exists on the books in many states, and is constitutionally permitted in circumstances essentially identical to those where civil libels liability is constitutional. Defenses to libel that can result in dismissal before trial include the statement being one of opinion rather than fact or being "fair comment and criticism," though neither of these are imperatives on the US constitution. Truth is always an absolute defense against a defamation suit in the United States.
Most states recognize that some categories of false statements are considered to be defamatory per se, such that people making a defamation claim for these statements do not need to prove that the statement was defamatory. (See section Defamation per se.)
Laws regulating slander and libel in the United States began to develop even before the American Revolution. In one of the most famous cases, New York publisher John Peter Zenger was imprisoned for 8 months in 1734 for printing attacks on the governor of the colony. Zenger won his case and was acquitted by jury in 1735 under the counsel of Andrew Hamilton. The case established some precedent that the truth should be an absolute defense against libel charges. Previous English defamation law had not provided this guarantee. Gouverneur Morris, a major contributor in the framing of the U.S. Constitution said, "The trial of Zenger in 1735 was the germ of American freedom, the morning star of that liberty which subsequently revolutionized America."
Zenger's case also established that libel cases, though they were civil rather than criminal cases, could be heard by a jury, which would have the authority to rule on the allegations and to set the amount of monetary damages awarded.
The First Amendment of the U.S. Constitution was designed specifically to protect freedom of the press. However, for most of the history of the United States, the Supreme Court neglected to use it to rule on libel cases. This left libel laws, based upon the traditional common law of defamation inherited from the English legal system, mixed across the states.
In 1964, however, the court issued an opinion in New York Times Co. v. Sullivan, 376 U.S. 254 (1964) dramatically changing the nature of libel law in the United States. In that case, the court determined that public officials could win a suit for libel only if they could demonstrate "actual malice" on the part of reporters or publishers. In that case, "actual malice" was defined as "knowledge that the information was false" or that it was published "with reckless disregard of whether it was false or not." This decision was later extended to cover "public figures", although the standard is still considerably lower in the case of private individuals.
In Gertz v. Robert Welch, Inc., 418 U.S. 323 (1974), the Supreme Court suggested that a plaintiff could not win a defamation suit when the statements in question were expressions of opinion rather than fact. In the words of the court, "under the First Amendment, there is no such thing as a false idea". However, the Court subsequently rejected the notion of a First Amendment opinion privilege, in Milkovich v. Lorain Journal Co., 474 U.S. 953 (1985). In Gertz, the Supreme Court also established a mens rea or culpability requirement for defamation; states cannot impose strict liability because that would run afoul of the First Amendment. This holding differs significantly from most other common law jurisdictions, which still have strict liability for defamation.
In Hustler Magazine v. Falwell, 485 U.S. 46 (1988), the Supreme Court ruled that a parody advertisement claiming Jerry Falwell had engaged in an incestuous act with his mother in an outhouse, while false, could not allow Falwell to win damages for emotional distress because the statement was so obviously ridiculous that it was clearly not true; an allegation believed by nobody, it was ruled, brought no liability upon the author. The court thus overturned a lower court's upholding of an award where the jury had decided against the claim of libel but had awarded damages for emotional distress.
After Stratton Oakmont, Inc. v. Prodigy Services Co., 1995 N.Y. Misc. Lexis 229 (N.Y. Sup. Ct. May 24, 1995), applied the standard publisher/distributor test to find an online bulletin board liable for post by a third party, Congress specifically enacted 47 U.S.C. § 230 (1996) to reverse the Prodigy findings and to provide for private blocking and screening of offensive material. § 230(c) states "that no provider or user of an interactive computer shall be treated as a publisher or speaker of any information provided by another information content provider," thereby providing forums immunity for statements provided by third parties. Thereafter, cases such as Zeran v. America Online, 129 F.3d 327 (4th Cir. 1997), and Blumenthal v. Drudge, 992 F. Supp. 44 (D.D.C. 1998), have demonstrated that although courts are expressly uneasy with applying § 230, they are bound to find providers like AOL immune from defamatory postings. This immunity applies even if the providers are notified of defamatory material and neglect to remove it, because provider liability upon notice would likely cause a flood of complaints to providers, would be a large burden on providers, and would have a chilling effect on freedom of speech on the Internet.
To solve the problem of libel tourism, the SPEECH Act makes foreign libel judgments unenforceable in U.S. courts, unless those judgments are compliant with the U.S. First Amendment. The act was passed by the 111th United States Congress and signed into law by President Barack Obama.
Defamation law in modern practice 
Defamation law in the United States is much less plaintiff-friendly than its counterparts in European and the Commonwealth countries, due to the enforcement of the First Amendment. One very important distinction today is that European and Commonwealth jurisdictions adhere to a theory that every publication of a defamation gives rise to a separate claim, so that a defamation on the Internet could be sued on in any country in which it was read, while American law only allows one claim for the primary publication.
In the United States, a comprehensive discussion of what is and is not libel or slander is difficult, because the definition differs between different states. Some states codify what constitutes slander and libel together into the same set of laws. Some states have criminal libel laws on the books, though these are old laws which are very infrequently prosecuted. Washington State has held its criminal libel statute unconstitutional applying the state and federal constitutions to the question.
Most defendants in defamation lawsuits are newspapers or publishers, which are involved in about twice as many lawsuits as are television stations. Most plaintiffs are corporations, businesspeople, entertainers and other public figures, and people involved in criminal cases, usually defendants or convicts but sometimes victims as well. In no state can a defamation claim be successfully maintained if the allegedly defamed person is deceased.
Section 230 of the Communications Decency Act of 1996 generally immunizes from liability parties that create forums on the Internet in which defamation occurs from liability for statements published by third parties. This has the effect of precluding all liability for statements made by persons on the Internet whose identity cannot be determined.
In the various states, whether by case law or legislation, there are generally several "privileges" that can get a defamation case dismissed without proceeding to trial. These include the litigation privilege, which makes statements made in the context of litigation non-actionable, and the allegedly defamatory statement being "fair comment and criticism", as it is important to society that everyone be able to comment on matters of public interest. The United States Supreme Court, however, has declined to hold that the "fair comment" privilege is a Constitutional imperative.
One defense is reporting or passing through information as a general information or warning of dangerous or emergent conditions, and intent to defame must be proven. Also, the truth of the allegedly defamatory statement will always negate the claim (whether because the plaintiff fails to meet his/her burden of proving falsity or because the defendant proves the statement to be true).
Defamation per se 
All states except Arizona, Arkansas, Missouri, and Tennessee recognize that some categories of false statements are so innately harmful that they are considered to be defamatory per se. In the common law tradition, damages for such false statements are presumed and do not have to be proven.
Statements are defamatory per se where they falsely impute to the plaintiff one or more of the following things:
- Allegations or imputations "injurious to another in their trade, business, or profession"
- Allegations or imputations "of loathsome disease" (historically leprosy and sexually transmitted disease, now also including mental illness)
- Allegations or imputations of "unchastity" (usually only in unmarried people and sometimes only in women)
- Allegations or imputations of criminal activity (sometimes only crimes of moral turpitude)
Criminal defamation 
On the federal level, there are no criminal defamation or insult laws in the United States. However, on the state level, seventeen states and two territories as of 2005 had criminal defamation laws on the books: Colorado (Colorado Revised Statutes, § 18-13-105), Florida (Florida Statutes, § 836.01-836.11), Idaho (Idaho Code, § 18-4801-18-4809), Kansas (Kansas Statute Annotated, §21-6103(a)(1)), Louisiana (Louisiana R.S., 14:47), Michigan (Michigan Compiled Laws, § 750.370), Minnesota (Minnesota Statutes. § 609.765), Montana (Montana Code Annotated, § 13-35-234), New Hampshire (New Hampshire Revised Statute Annotated, § 644:11), New Mexico (New Mexico Statute Annotated, §30-11-1), North Carolina (North Carolina General Statutes, § 14-47), North Dakota (North Dakota Century Code, § 12.1-15-01), Oklahoma (Oklahoma Statutes, tit. 21 §§ 771-781), Utah (Utah Code Annotated, § 76-9-404), Virginia (Virginia Code Annotated, § 18.2-417), Washington (Washington Revised Code, 9.58.010 [Repealed in 2009]), Wisconsin (Wisconsin Statutes, § 942.01), Puerto Rico (Puerto Rico Laws, tit. 33, §§ 4101-4104) and Virgin Islands (Virgin Islands Code, Title 14, § 1172).
Between 1992 and August 2004, 41 criminal defamation cases were brought to court in the United States, among which six defendants were convicted. From 1965 to 2004, 16 cases ended in final conviction, among which nine resulted in jail sentences (average sentence, 173 days). Other criminal cases resulted in fines (average fine, 1700 USD), probation (average of 547 days), community service (on average 120 hours), or writing a letter of apology.
- attributed to Gouverneur Morris by John Francis, Edinburgh Encyclopedia, American Edition, page 400
- Unfettered Press: Libel Law in the United States
- Rickert v. Washington (Wash. 2007)
- "Libel, and Slander Per Se". dancingwithlawyers.com. Retrieved 2009-07-09.
- Larson, Aaron (August 2003). "Defamation, Libel and Slander Law". ExpertLaw. Retrieved 2009-07-09.
- Chapter 9.58 RCW Dispositions
- OSCE – Libel and Insult Laws: A Matrix on Where We Stand and What We Would Like to Achieve (see page 171; report on the United States provided by HELLER, Dave, from the Media Law Resource Center)
- OSCE – Libel and Insult Laws: A Matrix on Where We Stand and What We Would Like to Achieve (op.cit., see page 172)