Due Process of Law

We can trace the concept of due process of law back to the Magna Carta in 1215. In 1354, the term was first used by the English Parliament, when it barred the government from imprisoning anyone "without being brought in answer by due process of law." 

In the US Constitution, there are two "due process" clauses – one in the Fifth Amendment, that applies to the actions of the federal government; and one in the Fourteenth Amendment, that applies to the states. 

There are also two kinds of "due process."  Procedural due process concerns the processes or procedures that will be used to ensure fair treatment, such as the right to a fair trial, with an impartial jury, etc.  Substantive due process defines what are the basic or substantive rights that everyone must have.  

Beginning in the 1960s, the US Supreme Court used the Fourteenth Amendment's due process clause to "incorporate" substantive rights – fundamental parts of the Bill of Rights that were seen to be essential for everyone – and apply them to the states.