Due process requires there be fair laws and a fair process
Our Bill of Rights contains what is called a due process clause, which explicitly prohibits the government from taking or failing to take any action that would deprive a person of “life, liberty, or property without due process of law.”
When a person is treated unfairly by the government through its body of laws and its civil and criminal procedures, the person is said to have been denied or deprived of due process of the law. The right to due process is a constitutionally protected right under the 14th and 5th Amendments.
The right to due process is considered a fundamental right which means it’s constitutionally and expressly mandated that every person in a civil or criminal matter is entitled to a fair process and fair laws.
A fair process is what courts call procedural due process. The actual laws under which a criminal or civil action is based are called “substantive” due process. To be deprived of either is a denial of both and renders the action unconstitutional.