The situation that describes a violation of the due process clause under the Fourteenth Amendment is:
The police performed a search on Stanley's house for illegal substances even though they did not have a search warrant. When they found a trunk full of illegal substances, they arrested Stanley.
This situation represents a clear violation of due process because the police conducted a search without having the legal authority of a search warrant, which is required to legally search someone's property. This lack of a warrant undermines the protections afforded by the Fourth Amendment (which is applicable to the states through the Fourteenth Amendment) and violates Stanley's due process rights.