Due process is the legal requirement that the state must respect all legal rights that are owed to a person. Due process balances the power of law of the land and protects the individual person from it. When a government harms a person without following the exact course of the law, this constitutes a due process violation, which offends the rule of law.
Due process has also been frequently interpreted as limiting laws and legal proceedings (see substantive due process) so that judges, instead of legislators, may define and guarantee fundamental fairness, justice, and liberty. That interpretation has proven controversial. Analogous to the concepts of natural justice, and procedural justice used in various other jurisdictions, the interpretation of due process is sometimes expressed as a command that the government must not be unfair to the people or abuse them physically. The term is not used in contemporary English law, but two similar concepts are natural justice, which generally applies only to decisions of administrative agencies and some types of private bodies like trade unions, and the British constitutional concept of the rule of law as articulated by A. V. Dicey and others. However, neither concept lines up perfectly with the American theory of due process, which, as explained below, presently contains many implied rights not found in either ancient or modern concepts of due process in England.
Due process developed from clause 39 of the Magna Carta in England. Clause 39 states "No man shall be arrested or imprisoned ... except by the lawful judgement of his peers or by the law of the land." When English and American law gradually diverged, due process was not upheld in England but became incorporated in the US Constitution.
In clause 39 of Magna Carta, issued in 1215, John of England promised: "No free man shall be seized or imprisoned, or stripped of his rights or possessions, or outlawed or exiled, or deprived of his standing in any other way, nor will we proceed with force against him, or send others to do so, except by the lawful judgment of his equals or by the law of the land." Magna Carta itself immediately became part of the "law of the land", and Clause 61 of that charter authorized an elected body of 25 barons to determine by majority vote what redress the King must provide when the King offends "in any respect against any man." Thus, Magna Carta established the rule of law in England by not only requiring the monarchy to obey the law of the land but also limiting how the monarchy could change the law of the land. However, in the 13th century, the provisions may have been referring only to the rights of landowners, and not to ordinary peasantry or villagers.