Vagueness doctrine

In, a  is void for vagueness and unenforceable if it is too vague for the average citizen to understand or if a term cannot be strictly defined and is not defined anywhere in such law, thus violating the. There are several reasons a statute may be considered vague; in general, a statute might be called void for vagueness reasons when an average citizen cannot generally determine what persons are regulated, what conduct is prohibited, or what punishment may be imposed. For example, criminal laws which do not state explicitly and definitely what conduct is punishable are void for vagueness. A statute is also void for vagueness if a legislature's delegation of authority to judges and/or administrators is so extensive that it would lead to arbitrary prosecutions. Related to the "void for vagueness" concept is the "unconstitutional vagueness" concept.

The "void for vagueness" doctrine applies only to criminal or penal laws (or quasi-criminal laws, for example laws that carry civil penalties), and laws that potentially limit constitutional rights. The doctrine does not apply to private law (that is, laws that govern rights and obligations as between private parties), only to laws that govern rights and obligations vis-a-vis the government. The doctrine requires that to qualify as constitutional, a law must:
 * State explicitly what it mandates, and what is enforceable.
 * Potentially vague terms must be defined.

Roots and purpose
In the case of vagueness, a statute might be considered void on constitutional grounds. Specifically, roots of the vagueness doctrine extend into the two due process clauses, in the and  Amendments to the United States Constitution. The courts have generally determined that vague laws deprive citizens of their rights without fair process, thus violating.

The following pronouncement of the void for vagueness doctrine was made by in ,, 391 (1926):

"[T]he terms of a penal statute [...] must be sufficiently explicit to inform those who are subject to it what conduct on their part will render them liable to its penalties… and a statute which either forbids or requires the doing of an act in terms so vague that men of common intelligence must necessarily guess at its meaning and differ as to its application violates the first essential of due process of law."

The void for vagueness doctrine is a constitutional rule. This rule requires that laws are so written that they explicitly and definitely state what conduct is punishable. The vagueness doctrine thus serves two purposes. First: All persons receive a fair notice of what is punishable and what is not. Second: The vagueness doctrine helps prevent arbitrary enforcement of the laws and arbitrary prosecutions. There is however no limit to the conduct that can be criminalized, when the legislature does not set minimum guidelines to govern law enforcement.

Specific application
There are at least two ways a law might be attacked for being unconstitutionally vague:


 * When a law does not specifically enumerate the practices that are either required or prohibited. In this case, the ordinary citizen does not know what the law requires. See also  (1971) and  (2012).
 * When a law does not specifically detail the procedure followed by officers or judges of the law. As a guard, a law must particularly detail what officers are to do, providing both for what they must do and what they must not do.  Judges must, under the doctrine, have a clear understanding of how they are to approach and handle a case. See also  (1983).

Both and objective criteria that specify the harm to be protected against are necessary to limit vagueness in criminal statutes (Compare page 9 of ). To satisfy the Due Process Clause of the Fifth Amendment, individuals are entitled to understand the scope and nature of statutes which might subject them to criminal penalties. Thus, in  (2010), it was held that a "penal statute must define the criminal offense (1) with sufficient definiteness that ordinary people can understand what conduct is prohibited and (2) in a manner that does not encourage arbitrary and discriminatory enforcement."

Unconstitutional vagueness
Unconstitutional vagueness is a concept that is used to strike down certain laws and judicial actions in s. It is derived from the doctrine found in the  and  to the. No one must risk criminal prosecution merely because they cannot reasonably understand what conduct is prohibited under the law. Laws which tend to fall under this category as being unconstitutionally vague usually contain broad language which is not defined anywhere else within the law (words and phrases such as annoy, profanity, and best practices).

Examples of unconstitutional vagueness

 * The, in  (Fla, 1971), ruled that the state's felony ban on sodomy was unconstitutionally vague because an "average person of common intelligence" could not reasonably know, without speculating, whether "abominable and detestable crime against nature" included oral sex or only anal sex.
 * ' (1972) and ' (1983) were two cases where the court struck down laws against  for unconstitutional vagueness; in restricting activities like "loafing", "strolling", or "wandering around from place to place", the law gave arbitrary power to the police and, since people could not reasonably know what sort of conduct is forbidden under the law, could potentially criminalize innocuous everyday activities.
 * In  (1982), the Supreme Court considered a pre-enforcement challenge to a municipal ordinance imposing licensing requirements and other restrictions on stores that sold . The Court sided with the village, holding that in such a lawsuit the plaintiff must demonstrate that the law would be "impermissibly vague in all its applications."
 * The U.S. Supreme Court, in  (1983), struck down a provision of 's abortion law which required that physicians dispose of fetal remains in a "humane and sanitary manner". "Humane" was judged to be unconstitutionally vague as a "definition of conduct subject to criminal prosecution"; the physician could not be certain whether or not his conduct was legal.
 * The has been ruled to be so imprecise as to be unconstitutional as applied to certain defendants.
 * The ruled that a  condition prohibiting a defendant from possessing "all forms of pornography, including legal adult pornography" was unconstitutionally vague because it posed a real danger that the prohibition on pornography might ultimately translate to a prohibition on whatever the officer personally found.
 * In (2012), the court ruled that since the words "obscene," "vulgar," "profane," and "indecent," were not accurately defined by the, it was unconstitutionally vague to enforce the restrictions against "obscene," "vulgar," "profane," or "indecent" acts since any person may see different things as obscene, vulgar, profane, or indecent. This was also compounded by the fact that the FCC allowed some words such as "shit" and "fuck" permissible to utter or state in some, but unclear, circumstances; but this was only seen as an accessory to the aforementioned reason.
 * In (2015), the Supreme Court ruled that the residual clause in the  was unconstitutionally vague and a violation of due process. The residual clause provided for an enhanced prison sentence for people who had previously been convicted of 3 or more violent felonies, which was defined as "use of physical force against the person of another," "burglary, arson, or extortion," "involves use of explosives," or "otherwise involves conduct that presents a serious potential risk of physical injury to another." The last part is known as the residual clause. The court determined that the residual clause was unconstitutionally vague because of the combination of two factors: (1) it focused on the ordinary case of a felony, rather than statutory elements or the nature of the convicted's actions, leaving significant uncertainty about how to assess the risk posed by a crime and (2) the clause does not give an indication of how much risk is necessary to qualify as a violent felony. Johnson's case—the fifth U.S. Supreme Court case about the meaning of the residual clause—involved whether possession of a short-barrelled shotgun was a violent felony.
 * In  (2018), the court ruled that a statute defining certain "aggravated felonies" for immigration purposes, is unconstitutionally vague. Justice, in a concurring opinion, stressed the dangers of vague laws.