Background material on the case of Mapp v. Ohio interprets the Supreme Court's holding that evidence obtained by an illegal police search and seizure is not admissible in court. The background information on the Shepherd v. Massachusetts decision interprets the Supreme Court's development of the 'good faith' exception to the exclusionary rule, which holds that when police act properly in obtaining a warrant and executing a search, even though the warrant itself may be flawed, the evidence obtained in the search is admissible in court. Professor Kamisar, when questioned about the appropriateness and effectiveness of the exclusionary rule, argues that the exclusion of illegally obtained evidence simply places the police where they would be in their investigation had they not acted illegally. Associate Attorney General Jensen argues that the exclusionary rule has the effect of neither punishing the police responsible for the illegal search nor punishing an offender whose crime is proven by the illegally obtained evidence; he views the exclusionary rule as a punishment of society, because it releases a criminal back into the community and fails to ensure society that the courts do justice. Kamisar counters that it is the fourth amendment that costs society, not the exclusionary rule, because it intends that the privacy rights of all citizens, criminals as well as innocent persons, are to be protected. Both men support the Supreme Court's 'good faith' interpretation of the exclusionary rule.