What legal concept helps maintain the integrity of the justice system?

The exclusionary rule is a legal principle that helps maintain the integrity of the justice system by ensuring that evidence obtained in violation of a person's constitutional rights cannot be used in court. This rule serves as a check against unlawful police conduct and upholds the Fourth Amendment, which protects individuals from unreasonable searches and seizures. By disallowing illegally obtained evidence, the exclusionary rule reinforces the idea that the ends do not justify the means in a fair justice system. It effectively prevents law enforcement from using improper methods to obtain evidence that might contribute to a conviction, thereby preserving the rule of law and protecting individual rights.

Other options, while relevant to legal processes, do not specifically maintain the integrity of the justice system in the same direct manner as the exclusionary rule. Double jeopardy protects individuals from being tried twice for the same offense, due process ensures fair legal procedures, and subpoena power allows for the gathering of evidence and testimony, but none of these directly address the exclusion of evidence obtained unlawfully, which is crucial for maintaining the justice system's integrity.