Law is the activity of subjecting human behavior to the governance of rules. The rule of law is concerned with regulating the use of power. Whereas society is a spontaneous order, the state is a protective agent with the monopoly role of enforcing the rules of the game. Since the monopoly on coercion belongs to the government, it is imperative that this power not be misused. Under the rule of law, everyone is bound by rules, including the government. The rule of law requires law to be: general and abstract, known and certain, and equally applicable to all people. The rule of law also necessitates independent judges unmotivated by political considerations and protection of a private domain of action and property.

In a free society each person has a recognized private sphere, a protected realm which government authority cannot encroach upon. The purpose of law is to preserve freedom and moral agency. The rule of law is a meta-legal principle. Similar to natural law theory, it provides a benchmark against which laws can be evaluated. From this perspective, law is about the discovery of the rules of just conduct. Following these rules leads us to examine what the main functions of law are and why they exist. The purpose of a legal system is to provide a systematic, orderly, and predictable mechanism for resolving disagreements. In order to do its job, any such system must perform three closely connected, but nevertheless distinct, functions: adjudication, legislation, and execution.

The judicial function is the core of any legal system. In its judicial function, a legal system adjudicates disputes, issuing a decision as to how the disagreement should be settled. The other two functions are merely adjuncts to this central function.

The purpose of the legislative function is to determine the rules that will govern the process of adjudication. Legislation tells judicial function how to adjudicate. The legislative process may be distinct from the judicial process, as when the Congress passes laws and the Supreme Court then applies them; or the two processes may coincide, as when a common-law body of legislation arises through a series of judicial precedents.

Finally, the purpose of the executive function is to ensure, first, that the disputing parties submit to adjudication in the first place, and second,.