The constitution guarantees various rights to fair procedures for those who are accused of crimes, involved in lawsuits, or subject to other threats of adverse governmental action – for example, being fired from certain government jobs or suspended from public schools. Perhaps the most important and basic procedural rights come from the Due Process Clauses of the Fifth and Fourteenth Amendments, which forbid governmental actions that deprive any person “of life, liberty, or property, without due process of law.”

Constitutional guarantees of fair procedures serve at least two functions. One is to promote accurate decision-making. The police may believe that they know who committed a crime and that a trial would be a waste of time and money, but the police may be wrong. The Constitution therefore guarantees the defendant a trial, with the right to hear and confront adverse witnesses. Similarly, a school principal may think, based on a teacher's report, that a child deserves to be suspended. Again, however, the story may have another side. The Due Process Clause guarantees the child at least an informal hearing, to make sure that the decision-maker has all relevant facts.