Mapp v. Ohio
A landmark case
Dollree Mapp was believed to be housing a bombing suspect. The police entered her home without a search warrant, and did not find the fugitive. However, they did find pornographic material which was banned in Ohio a the time. Mapp sued under the First Amendment claiming that the law which had banned the material was unconstitutional, however, The Supreme Court ruled under the fourth.
The fourth and fourteenth amendment were at issue in this case. The authorities did not have the proper search warrant to search for the obscene material, and did not have probable cause to search her home. Due to the procedural due process clause and incorporation doctrine, the fourth amendment became applicable to the states. Through this, the evidence used against Mapp had to be excluded because it was seized in violation of the fourth amendment.
The exclusionary rule was established which stated that evidence collected or analyzed in violation of the defendant's constitutional rights can be inadmissible for a criminal prosecution court.
The ruling which placed Mapp in prison was overturned and the exclusionary rule was established which prevented illegally obtained evidence from being used in court.
The overall need for a search warrant and the 4th amendment still applies, however the decision has been undermined through exceptions such as if the officer believes his/her search is legal or if the piece of evidence would have been eventually discovered legally, then it would be admissible in court. The precedent established could be applicable today to things such as the Patriot Act in attempt to stop terrorist attacks.
The court still maintains this policy, however it has made exceptions to the exclusionary rule and what is deemed legal seizure. The principal could be applied to anything as long as there is illegal material that authorities would need to confiscate.