Law is a system of rules that governments and societies use to deal with crime, business agreements, and social relationships. It can also refer to the people who work in this system, such as police officers or judges.
Definitions of law vary, but a common view is that it is a set of rules that are in the best interest of the community and which are enforced by individuals. Utilitarian theories of law based on natural laws, such as those of Jeremy Bentham, suggest that law is a set of essentially moral rules.
Legal power is the ability to alter a legal position, relation or norm (Raz 1970; MacCormick 1977). A legally recognized power can be attributed to the state, a person in his capacity as an officer of the state, or a private individual.
Justification is the legal grounding of a right or a duty (MacCormick 1982; Raz 1994; Wellman 1995). A right may be justified by an unspecified or underdetermined duty correlating to it.
Typically, legal justification involves a vested duty or a law that grounds it as a matter of law (MacCormick 1977; Sumner 1987; Raz 1994).
In a nation, law can serve to keep the peace, maintain the status quo, protect individuals from oppression, and promote social justice. Some legal systems serve these purposes better than others.