Legality is the state of being consistent with the law, the construct of legal power, or lawfulness in a given jurisdiction. [1]
Feminist theories of law define legality a distinct but related concept to the law, consisting of socially-constructed meanings and practices that depend on social forces, such as race, gender, and class. [2] Ewick and Sibley define "legality" as "those meanings, sources of authority, and cultural practices that are commonly recognized as legal, although not necessarily approved nor acknowledged by law." [3] [4]
In contract law, legality of purpose is required of every enforceable contract. One can not validate or enforce a contract to do activity with unlawful purpose. [5]
The principle that no one be convicted of a crime without a written legal text which clearly describes the crime is widely accepted and codified in modern democratic states as a basic requirement of the rule of law. It is known in Latin as nulla poena sine lege .
Nulla poena sine lege is a principle of international human rights law and is incorporated into the Universal Declaration of Human Rights, the International Covenant on Civil and Political Rights and the European Convention on Human Rights. Exceptionally under international law, criminal offences may include violations of "the general principles of law recognized by civilized nations", such as genocide, war crimes and crimes against humanity, even if such offences are not codified or affirmed in judicial precedent. Following the Nuremberg trials, scholars of jurisprudence have debated whether such exceptions are valid for apparently applying retrospective criminal sanctions in the absence of written law. Natural-law theorists argue that crimes such as genocide are, and have always been, illegal under natural law.
In the United Kingdom under the doctrine of Parliamentary sovereignty, the legislature can (in theory) pass such retrospective laws as it sees fit, though article 7 of the European Convention on Human Rights, which has legal force in Britain, forbids conviction for a crime which was not illegal at the time it was committed.
In the United States, laws may not violate the stated provisions of the United States Constitution, which includes a prohibition on retrospective laws.