's conviction because, as Justice Tom Clark explained in his majority opinion that the Fourth Amendment's ban on illegal searches and seizures was applicable in state courts through the application of the Due Process Clause of the Fourteenth Amendment. The majority further held that the exclusionary rule barred the use of such evidence in state as well as federal courts. The basic rationale of the majority was that the right of privacy implicit in the Fourth Amendment could only be protected if the courts where most criminal trials took place, namely, state courts, abided by the exclusionary rule; that the application of that rule was needed to deter police from engaging in illegal searches and seizures such as that which had occurred in the Mapp case; and to discourage state prosecutors from using such 'fruit of the poisonous tree' as evidence in state criminal trials. Clark went on to say that cooperation between federal and state law enforcement authorities would be promoted by the Court's ruling.
In his concurring opinion, Justice Hugo Black expressed doubt that the Fourth Amendment alone would justify the result reached by the Court but he said the police conduct also violated the Fifth Amendment's ban against forced self-incrimination and on that basis he concurred. In his concurring opinion, Justice William Douglas emphasized at p. 669 that failure to apply the exclusionary rule to illegal searches and seizures would "rob the Fourth Amendment of much meaningful force." He described other remedies such as suits against police officers for trespass or internal law enforcement disciplinary actions against such officers as illusory.
In his dissenting opinion in which Justices Felix Frankfurter, Justice Charles Whittaker and Justice Potter Stewart joined, Justice John Harlan argued hat the holding of the majority departed from the principle of stare decisis, the binding nature generally of prior precedents set by the Court, an...