Reading Room Document

Searches and Seizures Under the Fourth Amendment

This memo summarized “important principles [of the Fourth Amendment] which have not been weakened by passage of time, the impact of the Federal Rules of Criminal Procedure, and several recent cases which indicate the trend that the law has taken.” At a high level, the memo described the law governing the issuance of valid search warrants, and explained the law at the time that even a warrant would not justify the search of a person’s private papers “merely for the purpose of using it against the accused in trial.” The memo also identified situations in which searches and seizures without warrants were permissible, including searches incidental to arrest and searches in emergency situations with probable cause. The memo ended with a list of seven miscellaneous “principles,” including that the Fourth Amendment does not prohibit wiretapping, and does not prohibit the use of illegally seized materials in a state prosecution.

March 15, 1954