Final answer:
The Supreme Court ruled in Mapp v. Ohio that the Fourteenth Amendment does require the exclusion of evidence obtained via unreasonable searches and seizures in state court prosecutions, establishing the 'fruit of the poisonous tree' principle thereby applying the exclusionary rule to the states.
Step-by-step explanation:
According to the Supreme Court, the Fourteenth Amendment does not forbid the admission of evidence obtained by an unreasonable search and seizure for a prosecution in a state court for a crime. This was established in the landmark case Mapp v. Ohio, where the Court held that evidence obtained in violation of the Fourth Amendment is inadmissible in state court. The decision in Mapp v. Ohio extended the protection against unreasonable searches and seizures, previously applicable only in federal cases, to state-level cases as well, through the Due Process Clause of the Fourteenth Amendment. Thus, the exclusionary rule, which prohibits the use of evidence obtained through an illegal search or seizure, applies to the states.
The importance of this ruling lies in its upholding of the principle known as the "fruit of the poisonous tree", which asserts that not only is the direct evidence obtained illegally inadmissible, but also any further evidence derived from the initial illegal search or seizure.