Which case established the exclusionary rule for illegally obtained evidence?

The establishment of the exclusionary rule is pivotal in U.S. law, particularly regarding the admissibility of evidence obtained through illegal means. The case that solidified this principle is Mapp v. Ohio. In this landmark decision, the Supreme Court ruled that evidence obtained by unlawful searches and seizures could not be used in state courts. This case expanded the exclusionary rule, previously applied only at the federal level, to the states through the incorporation doctrine of the Fourteenth Amendment.

The ruling was significant as it reinforced the Fourth Amendment rights of individuals against unreasonable searches. The Court determined that allowing illegally obtained evidence to be used in court would undermine the integrity of the judicial system and the protections guaranteed to individuals under the Constitution. Mapp v. Ohio thus set a critical legal precedent, emphasizing the importance of lawful procedures when obtaining evidence, which directly impacts the conduct of law enforcement and protects citizens’ rights.