The rule of law, in its most basic form, is the principle that no one is above the law. It has been said that the rule follows logically from the idea that truth, and therefore law, is based upon fundamental principles which can be discovered, but which cannot be created through an act of will. But human law is not necessarily based on truth.

In England, the issuing of the Magna Carta was a prime example of the "rule of law." The Great Charter forced King John to submit to the law and succeeded in putting limits on feudal fees and duties.

Perhaps the most important application of the rule of law is the principle that governmental authority is legitimately exercised only in accordance with written, publicly disclosed laws adopted and enforced in accordance with established procedural steps that are referred to as due process. The principle is intended to be a safeguard against arbitrary governance, whether by a totalitarian leader or by mob rule. Thus, the rule of law is hostile both to dictatorship and to anarchy. Samuel Rutherford was one of the first modern authors to give the principle theoretical foundations, in Lex, Rex (1644), and later Montesquieu in The Spirit of the Laws (1748).