What does the exclusionary rule prevent?

The exclusionary rule is a fundamental principle in criminal procedure that aims to deter law enforcement from violating individuals' constitutional rights. Specifically, it prevents the use of evidence that has been obtained in violation of a defendant's Fourth Amendment rights, which guard against unreasonable searches and seizures. If evidence is collected without a proper warrant or probable cause, or in violation of other constitutional protections, it is deemed inadmissible in court. This encourages police to follow legal protocols and safeguards the integrity of the judicial system by ensuring that convictions are based on lawfully obtained evidence.

The other options do not accurately reflect the scope of the exclusionary rule. While confessions made without legal counsel are certainly problematic and can be challenged under different rights and rules, they are not specifically covered by the exclusionary rule. Witness testimonies, unless they directly involve evidence obtained through illegal means, are not automatically excluded. Lastly, the exclusionary rule does not interfere with the appeals process itself; it primarily pertains to the admissibility of evidence at trial.