Due process is arguably the most fundamental right enshrined under the Constitution. It developed from clause 39 of the Magna Carta in England in 1354: “No man of what state or condition he be, shall be put out of his lands or tenements nor taken, nor disinherited, nor put to death, without he be brought to answer by due process of law.”
Both the Fifth Amendment and the Fourteenth Amendment of the U.S. Constitution provide that no “Person” (not just citizens) “shall be deprived of life, liberty, or property” without due process of law. Thus the requirement of due process is imposed against both the federal government (by the Fifth Amendment) and the states (by the Fourteenth Amendment).
Due process has two components under United States law. The historical and traditional form of due process provides procedural rights against arbitrary or unauthorized government action. Such procedural due process rights have been held to include the right to a fair hearing, the right to a jury of one’s peers in a criminal case, the right to petition for habeas corpus, the right to cross-examine and confront adverse witnesses, the right to a lawyer, including a court-appointed lawyer in a criminal trial, the right not to be tried twice for the same alleged crime (double jeopardy), and numerous other procedural protections.
The second component of due process is referred to as substantive due process. It addresses the content of the liberty and property rights protected by the due process clauses. Among the rights protected by substantive due process are rights of privacy, right to use contraception, right to marry, right to raise children without undue state interference, the right not to be deprived of property without just compensation, rights to equal protection under the law, as well as most of the liberty rights otherwise established in the Constitution, the Bill of Rights (amendments 1-10), and later amendments to the Constitution. The rights of free speech and free exercise of religion are protected from the acts of the states by the due process clause of the Fourteenth Amendment.