Final answer:
Conclusive presumptions are unconstitutional under the Due Process Clause as they prevent a fair trial and deny individuals the opportunity to present evidence, which are key aspects of procedural justice safeguarded by the clause.
Step-by-step explanation:
Conclusive presumptions are considered unconstitutional under the Due Process Clause because they violate the principle that the government must respect all legal rights owed to a person. The Due Process Clause ensures fairness in legal processes and prohibits arbitrary denial of life, liberty, or property.
A conclusive presumption eliminates an individual's opportunity to present evidence to the contrary, thus denying them a fair trial, which is a cornerstone of procedural justice. For example, Supreme Court cases like Sherbert v. Verner reflect the necessity of individual rights to fair treatment and the protection of fundamental liberties.