The rule of law is the legal principle that law should govern a nation, as opposed to being governed by arbitrary decisions of individual government officials. It primarily refers to the influence and authority of law within society, particularly as a constraint upon behaviour, including behaviour of government officials. The phrase can be traced back to 16th century Britain, and in the following century the Scottish theologian Samuel Rutherford used the phrase in his argument against the divine right of kings. John Locke defined freedom under the rule of law as follows:
The rule of law was further popularized in the 19th century by British jurist A. V. Dicey. The concept, if not the phrase, was familiar to ancient philosophers such as Aristotle, who wrote "Law should govern".
Rule of law implies that every citizen is subject to the law, including lawmakers themselves. In this sense, it stands in contrast to an , dictatorship, or oligarchy where the rulers are held above the law. Lack of the rule of law can be found in both democracies and dictatorships, for example because of neglect or ignorance of the law, and the rule of law is more apt to decay if a government has insufficient corrective mechanisms for restoring it. Government based upon the rule of law is called .
Although credit for popularizing the expression "the rule of law" in modern times is usually given to A. V. Dicey, development of the legal concept can be traced through history to many ancient civilizations, including ancient Greece, China, Mesopotamia, India, and Rome.
In the West, the ancient Greeks initially regarded the best form of government as rule by the best men.Plato advocated a benevolent monarchy ruled by an idealized philosopher king, who was above the law. Plato nevertheless hoped that the best men would be good at respecting established laws, explaining that "Where the law is subject to some other authority and has none of its own, the collapse of the state, in my view, is not far off; but if law is the master of the government and the government is its slave, then the situation is full of promise and men enjoy all the blessings that the gods shower on a state." More than Plato attempted to do, Aristotle flatly opposed letting the highest officials wield power beyond guarding and serving the laws. In other words, Aristotle advocated the rule of law: