What key principle was established in Wolf v. Colorado?

In Wolf v. Colorado, the Supreme Court held that the exclusionary rule, which prevents the use of illegally obtained evidence in criminal trials, is applicable to state courts through the due process clause of the Fourteenth Amendment. This landmark ruling marked a significant extension of the protections offered by the Fourth Amendment against unreasonable searches and seizures, affirming that states are required to uphold these rights.

By incorporating the exclusionary rule into state law, the court ensured that individuals' rights are protected at both the federal and state levels, promoting fair legal processes. This decision laid the groundwork for future cases that further solidified the application of constitutional protections against unlawful search and seizure across all jurisdictions, emphasizing that states cannot ignore federal constitutional standards regarding evidence obtained in violation of a defendant’s rights.