The Constitution states only one command twice. The Fifth Amendment says to the federal government that no one shall be "deprived of life, liberty or property without due process of law."
The Fourteenth Amendment, ratified in 1868, uses the same eleven words, called the Due Process Clause, to describe a legal obligation of all states. These words have as their central promise an assurance that all levels of American government must operate within the law ("legality") and provide fair procedures. Most of this article concerns that promise.
The clause also promises that before depriving a citizen of life, liberty or property, the government must follow fair procedures. Thus, it is not always enough for the government just to act in accordance with whatever law there may happen to be. Citizens may also be entitled to have the government observe or offer fair procedures, whether or not those procedures have been provided for in the law on the basis of which it is acting. Action denying the process that is “due” would be unconstitutional.
Suppose, for example, state law gives students a right to a public education but doesn't say anything about discipline. Before the state could take that right away from a student, by expelling her for misbehavior, it would have to provide fair procedures, i.e. “due process.”
In this case, we are talking about Procedural Due Process
Procedural due process
Procedural due process refers to the constitutional requirement that when the federal government acts in such a way that denies a citizen of a life, liberty, or property interest, the person must be given notice, the opportunity to be heard, and a decision by a neutral decision-maker.
Procedural due process is one of two of the components of due process, with the other being substantive due process.
Due Process Clause
In the U.S. Constitution, the phrase "due process" appears twice: in the Fifth Amendment and in the Fourteenth Amendment. Both Amendments guarantee due process when someone is denied "life, liberty, or property."
Possibly Guaranteed Procedures
Judge Henry Friendly, in this article titled "Some Kind of Hearing," created a list of required procedures that due process requires. While this list is not mandatory, it remains highly influential, both in its content and relative priority of each item.
An unbiased tribunal.
Notice of the proposed action and the grounds asserted for it.
Opportunity to present reasons why the proposed action should not be taken.
The right to present evidence, including the right to call witnesses.
The right to know opposing evidence.
The right to cross-examine adverse witnesses.
A decision based exclusively on the evidence presented.
Opportunity to be represented by counsel.
Requirement that the tribunal prepare a record of the evidence presented.
Requirement that the tribunal prepare written findings of fact and reasons for its decision.