Also known as: fair-warning · fair notice
Written by attorneys · grounded in primary & secondary sources — see below
A due process principle that requires laws imposing penalties or restrictions to define prohibited or required conduct with sufficient precision so that ordinary persons receive notice of what conduct is prohibited and enforcement officials receive guidance against arbitrary application.
Francois Fortier operated a manufacturing plant that released pollutants into a nearby river. A jury awarded the downstream homeowners $200,000 in compensatory damages and $25 million in punitive damages. Fortier argued on appeal that the size of the punitive award violated due process because the statutory penalties for comparable environmental violations were capped at $50,000 per incident.
Felix Franco stood on a street corner near a known gang area while waiting for a bus. Police officers ordered him to disperse under a city ordinance that criminalized remaining in one place with no apparent purpose. Franco was arrested after refusing to move and later challenged the ordinance as providing no clear standard for what conduct triggered enforcement.
Select any source to read its text and confirm it supports the definition.
Francesca Fiore, defense counsel in a high-profile fraud trial, told reporters that her client had been framed by overzealous prosecutors. The state bar charged her with violating a publicity rule that barred statements creating a substantial likelihood of material prejudice yet permitted statements about the general nature of the defense. Fiore moved to dismiss the charges on the ground that the rule left her without clear notice of the boundary between permissible and prohibited comments.
Farah Fox operated a bookstore that sold novels containing explicit sexual content. Federal prosecutors charged her under an obscenity statute after the Supreme Court adopted a new test focused on whether the material appealed to prurient interest and lacked redeeming social value. Fox moved to dismiss, contending that the new standard failed to give her advance notice that the books she had been selling would now be treated as criminal.
Faith Fitzgerald, a tenured public-school teacher, received a letter stating only that her contract would not be renewed. The school board later cited performance concerns at a hearing but had never previously warned her that those concerns could lead to termination. Fitzgerald sued, claiming the lack of prior notice deprived her of a meaningful opportunity to respond before the decision became final.
Fumiko Fujimoto walked through a neighborhood after dark carrying identification but refused a police officer's demand to produce it under a statute requiring persons on the street to provide credible and reliable identification. She was arrested and later moved to dismiss the charge, arguing that the statute supplied no objective standard for what counted as credible identification and therefore left ordinary citizens without fair notice of the required conduct.
The doctrine requires that a statute give a person of ordinary intelligence fair notice that contemplated conduct is forbidden and that the statute not encourage arbitrary and erratic arrests and convictions.
Fair warning implements the principle of legality by ensuring that criminal liability is imposed only after the legislature has clearly defined the prohibited conduct in advance rather than through after-the-fact judicial expansion.
Yes. Even a facially clear statute may deny fair warning when official statements or prior interpretations have affirmatively misled the defendant about the conduct's legality.
The statute is void for vagueness under the Due Process Clause and any conviction obtained under it must be reversed.
…or not the speech or press interest is clearly protected under substantive First Amendment standards. Thus, we have required fair notice and opportunity for an adversary hearing before an injunction is issued against the holding of rallies and public meetings. Carroll v. Princess Anne , 393 U. S. 175. Similarly, we have…