The idea of due process of law dates from England's Magna Carta of 1215. One article in this document promises that no one shall be deprived of life, liberty, or property, except "by the lawful judgment of his peers or by the law of the land." Some early English writs (written legal orders) were designed to bring the government under a rule of law. For example, a writ of habeas corpus requires that the government show just cause before it can hold a person in custody.

Through law and custom, various safeguards have been developed in the United States to assure that persons accused of wrongdoing will be treated fairly. These safeguards are sometimes called procedural due process. Procedural due process includes the following requirements: (1) The law must be administered fairly. (2) People must be informed of the charges against them and must be given the opportunity for a fair hearing. (3) The person bringing the charges must not be allowed to judge the case. (4) Criminal laws must be clearly worded so that they give adequate warning of the action prohibited. Procedural due process concepts apply to civil and criminal cases.

Courts have also used the "due process" clauses of the 5th and 14th amendments to limit the content of laws, even though there was no procedural unfairness. For example, they have declared unconstitutional some laws restricting personal freedoms and business, on the ground that the laws violate due process of law. This practice involves the substance of public policy and is called substantive due process.