What does the exclusionary rule prohibit?

• A. The use of hearsay evidence
• B. The use of illegally obtained evidence in a criminal trial
• C. The use of any physical evidence
• D. The use of expert testimony

Answer: (B)

The main concept is that the exclusionary rule bars the use in court of evidence obtained in violation of the Constitution, especially through illegal searches and seizures. This remedy exists to deter police misconduct and to protect individuals’ Fourth Amendment rights. In practice, it means if the only way to prove guilt relies on illegally obtained material (including its derivative fruits), that evidence cannot be admitted at trial. There are important exceptions, such as when the evidence would have been found anyway or was obtained in good faith reliance on a warrant that later turns out to be defective. This rule doesn’t blanketly exclude all evidence—lawful, independently obtained evidence can still be used. It also doesn’t automatically apply to hearsay or to expert testimony, which are governed by separate evidentiary rules; the exclusionary rule focuses specifically on evidence obtained illegally.