Unconstitutionally vague

In American constitutional law, a statute is void for vagueness and unenforceable if it is too vague for the average citizen to understand. 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. Criminal laws which do not state explicitly and definitely what conduct is punishable for example 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).

To summarize the contents of the doctrine, it establishes specific criteria all laws, or any legislation must meet, to qualify as constitutional. Such criteria includes the following:

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., 269 U.S. 385, 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 criminal laws are so written that they explicitly and definitely state what conduct is punishable. The void for 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.

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