There are a couple of different rationales advanced today for excluding illegally obtained evidence (this is called the "exclusionary rule"). One that you hear

There are a couple of different rationales advanced today for excluding illegally obtained evidence (this is called the "exclusionary rule"). One that you hear a lot is that it gives an incentive for police and prosecutors to respect constitutional rights as they do not want to have their cases dismissed. (Otherwise, there would be no legal consequences for conducting an illegal search.) It would also seem improper for a court to condone illegal searches by allowing the resulting evidence to be introduced. The rule originates in a 1914 Supreme Court case, Weeks v. United States[1]. In that case, the police searched a man's home without a warrant and then introduced papers seized in the search as evidence to convict him of running an illegal lottery. The court reasoned that this evidence must be excluded (and the conviction must be overturned) because to allow illegally obtained evidence to be used in a proceeding would "affirm by judicial decision a manifest neglect, if not an open defiance, of the prohibitions of the Constitution, intended for the protection of the people against such unauthorized action." In other words, if the 4th Amendment's protections against unreasonable searches and seizures are to mean anything, a Court cannot countenance the use of illegally obtained evidence. I think this reasoning is persuasive even if it seems a bit formalistic. The state only has the power to convict you when it is itself acting lawfully. A conviction based on evidence it did not have the authority to obtain is meaningless. [1]:https://supreme.justia.com/cases/federal/us/232/383/case.html https://supreme.justia.com/cases/federal/us/232/383/case.htm...