The law is a system of rules enforceable by governmental or social institutions. It serves many purposes, including establishing standards, maintaining order, resolving disputes, and protecting liberties and rights. For an exposition of the law’s limitations as a tool for achieving these goals, see the articles on censorship; crime and punishment; police; and war.

While the precise nature of law is a subject of long debate, it can be generally described as the body of legal principles, practices and precedents that guide a society. A legal system typically includes written statutes, regulations and executive orders; the courts; and the professional bodies that train lawyers and judges.

A legal system’s effectiveness depends on the integrity of its judicial and executive branches, and the impartiality and objectivity of its courts. The rule of law requires that citizens be held equal before the law, that laws are publicly promulgated and equally enforced, that government officials and entities be accountable for their actions, and that decisions of higher courts bind lower courts (the doctrine of stare decisis).

The legal profession has a unique responsibility to uphold the rule of law by preventing corrupt or biased actions by those in authority. It is also important to ensure that the public is adequately informed about the law and its application. This is accomplished through the media and through law schools, which prepare future lawyers for their careers.

Law is a human construct, which means that it cannot be empirically verified. Moreover, there is no way to determine whether any particular set of precepts is “right” or “just.” Thus, there is no objective basis for judging the legitimacy of any specific legal system.

While a wide variety of legal systems exist, most are based on some form of common law. This legal tradition, which dates back to medieval times, is rooted in the concept that judges and barristers should follow established precedent when deciding cases. In contrast, in civil law systems, the judicial decisions are less authoritative and binding.

The societal function of the law is to provide people with a sense of stability and predictability. In addition, the law should protect their personal and property rights, provide for free expression of ideas, maintain a stable financial system, and prevent the concentration of power in the hands of a few. This is an especially difficult challenge in modern societies, where military and policing forces extend far beyond the boundaries of a state and into the lives of its citizens. Modern forensic science and technology are developing new methods for verifying claims about events that may be difficult to establish through testimony alone. These developments will enhance the ability of prosecutors to prosecute crimes that would have been impossible to prove with previous technology. In some cases, the availability of such advances has already made a significant difference in criminal conviction rates. This is particularly true in cases of terrorism.