I think this is a fair high-level summary: “In United States constitutional law, a Due Process Clause is found in both the Fifth and Fourteenth Amendments to the United States Constitution, which prohibits arbitrary deprivation of life, liberty, or property by the government except as authorized by law. … The U.S. Supreme Court interprets these clauses broadly, concluding that they provide three protections: procedural due process (in civil and criminal proceedings); substantive due process, a prohibition against vague laws; and as the vehicle for the incorporation of the Bill of Rights.”
https://en.wikipedia.org/wiki/Due_Process_Clause#Incorporation_of_the_Bill_of_Rights
