根据《比较法研究》2015年第5期的论文《公众人物理论与真实恶意规则之检讨》，actual malice rule 被称为真实恶意规则，这个规则限制了公众人物以诽谤罪来阻止新闻媒体的报导自由。

以下解释源自维基百科

“真实恶意（英语：actual malice），也译为真正恶意、实际恶意、实质恶意，美国法律名词，是美国法院用来规范言论自由与出版自由的准则之一。这个原则在1964年美国最高法院（沃伦法院）审理纽约时报诉沙利文案时确立，由大法官小威廉·布伦南撰写多数意见，这个原则限缩了政府官员的名誉权，扩张了言论自由的范围。

这个原则限制了公众人物以诽谤罪来阻止新闻媒体的报导自由，以防止寒蝉效应。其背后的立场，主要在于限缩政治人物的隐私权，让公众有机会在言论的自由市场中，获得真相。但也同时带来公众人物难以回避不实指控的影响，特别是媒体受到操纵的情况下。反对者认为这个原则侵害了个人隐私权与名誉，减少新闻媒体的查证义务，助长了新闻媒体轻率报导的风气。

”在1964年纽约时报诉沙利文案（New York Times, Co. v. Sullivan, 376 U.S. 254)，美国联邦最高法院（沃伦法院）创设了真实恶意原则，在政治领域上，取代了真实抗辩原则。这个原则下是指政府官员（Public Officials）在指控媒体报导涉嫌诽谤或侵害名誉时，必须证明被告“明知其言论不实”（with knowledge the statement was false），或“对于其言论真实与否毫不在意”（with reckless disregard of whether the statement was false or not），才能够让名誉权受损事实成立。因为必须举证媒体报导中具备相当的主观恶意，这增加了政治人物对媒体侵害其名誉权的诉讼难度。 再经过一些判例发展，当被告疏于查证的情况已经相当于“蓄意的回避事实真相”（purposeful avoidance of the truth），才有可能构成真实恶意。

美国大法官作出这项判决的用意，在于大幅度增进言论自由的范围。在苏利文案判决中，说明，“对于公共议题的讨论应该要不受限制、强健有力，以及完全的开放（Uninhibited, Robust and Wide-Open），即使这些言论，可能包括对政府或政府官员尖酸刻薄及令人不快的攻击。”

https://zh.wikipedia.org/wiki/%E7%9C%9F%E5%AF%A6%E6%83%A1%E6%84%8F%E5%8E%9F%E5%89%87

英文相关解释：

“Actual malice in United States law is a legal requirement imposed upon public officials or public figures when they file suit for libel (defamatory printed communications). Unlike other individuals who are less well-known to the general public, public officials and public figures are held to a higher standard for what they must prove before they may succeed in a defamation lawsuit”

This term was adopted by the Supreme Court in its landmark 1964 ruling in New York Times Co. v. Sullivan, in which the Warren Court held that: The constitutional guarantees require, we think, a Federal rule that prohibits a public official from recovering damages for a defamatory falsehood relating to his official conduct unless he proves that the statement was made with 'actual malice'—that is, with knowledge that it was false or with reckless disregard of whether it was false or not. Although defined within the context of a media defendant, the rule requiring proof of actual malice applies to all defendants including individuals.[citation needed] The standard can make it very difficult to prevail in a defamation case, even when allegations made against a public figure are unfair or are proved to be false. Rather than being newly invented for the case, the term was a term from existing libel law. In many jurisdictions, proof of "actual malice" was required for punitive damages to be awarded or for other increased penalties. For example, Times v. Sullivan examined an existing Alabama statute that required proof of actual malice before an award of punitive damages would be permitted.Since proof of the writer's malicious intentions is hard to ascertain, proof that the writer knowingly published a falsehood was generally accepted as proof of malice, under the assumption that only a malicious person would knowingly publish a falsehood. In Sullivan, the Supreme Court adopted the term and gave it constitutional significance and defined it in terms of the proof that was usual. Proof of malice Actual malice is different from common law malice, a term that indicates spite or ill will. It may also differ from malice as defined in state libel law, as reflected in the 1983 case of Carol Burnett v. National Enquirer, Inc., although states may not define a lower threshold for defamation claims than that required by the First Amendment. The existence of actual malice may be shown in many ways, as long as the claim is properly supported by admissible evidence.[6] Malice may be proved through any competent evidence, either direct or circumstantial. All of the relevant circumstances surrounding the transaction may be shown, provided they are not too remote, including threats, other defamatory statements, subsequent statements made by the defendant, any circumstances that indicate the existence of rivalry, ill will, or hostility between the parties, and facts that tend to show a reckless disregard of the plaintiff's rights on the part of the defendant.”

https://en.wikipedia.org/wiki/Actual_malice

《伟大的瞬间或失败的制度：反思“沙利文规则”》一文中对于此规则做了较为全面的论述。