The Federal eavesdropping law does not define minimization or set forth any specific standards by which to determine if minimization has been properly carried out. The minimization clause has a constitutional basis, however, and represents a congressional response to two 1967 U.S. Supreme Court decisions involving the application of the fourth amendment to electronic surveillance. In Katz v. United States, the Supreme Court decided that the FBI's electronic monitoring of a public telephone booth constituted an unreasonable search and seizure because the agents did not obtain prior court authorization. In Berger v. New York, police officers had obtained judicial authorization for surveillance of a law office. However, the Supreme Court held that the State law lacked certain protective procedures. These decisions have defined minimization as requiring that monitoring officers make reasonable efforts to avoid seizing nonpertinent or innocent conversations, by not listening to and recording them. Both Congress and court decisions have acknowledged the impossibility of screening out all nonpertinent conversations. Courts have defined two types of minimization. Extrinsic minimization focuses on known time factors and limits the hours or duration of monitoring. Intrinsic minimization involves situations such as narcotics distribution, in which the times of criminal communications do not follow regular patterns. In these cases, the 1978 decision in Scott v. United States has established that the facts and circumstances of each case must be used to determine whether minimization was carried out properly. 30 footnotes.