Procedural due process is the means by which an accused exercises his or her rights of confrontation, to present witnesses, to be represented by counsel, and related rights. At its heart is the fundamental right of notice and an opportunity to be heard. Traditionally, these rights were enforced at the federal level through the Bill of Rights or Congressional mandate. At the state level, these rights — prior to the Fourteenth Amendment — were enforced through state constitution or state legislative mandate.