Vagueness doctrine

In American constitutional law, a statute is void for vagueness and unenforceable if it is too vague for the average citizen to understand, and a constitutionally-protected interest cannot tolerate permissible activity to be chilled within the range of the vagueness (either because the statute is a penal statute with criminal or quasi-criminal civil penalties, or because the interest invaded by the vague law is a strict scrutiny constitutional right). There are several reasons a statute may be considered vague; in general, a statute might be void for vagueness 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 (see below). A law can be "void for vagueness" if it imposes on First Amendment freedom of speech, assembly, or religion.
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 "strict scrutiny" 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:
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 Fifth and Fourteenth Amendments to the United States Constitution. The courts have generally determined that vague laws deprive citizens of their rights without fair process, thus violating due process.
The following pronouncement of the void for vagueness doctrine was made by Justice Sutherland in "Connally v. General Construction Co.", , 391 (1926):
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:
Both scienter 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 "Skilling v. United States" (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 United States federal courts. It is derived from the due process doctrine found in the Fifth and Fourteenth Amendments to the United States Constitution. 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).