One of the most powerful investigative tools available to law enforcement is electronic surveillance of wire, oral, and electronic communications, as well as silent video surveillance of areas. These techniques are also extremely invasive. Consequently, the Federal Congress and courts, as well as State legislature and courts, have sought to limit the use of electronic surveillance to only those times when its use is necessary. The necessity requirement may be satisfied if the standard techniques have been tried and failed or if investigators can explain why each technique would be futile in the particular investigation. Electronic surveillance is a Fourth Amendment search when it is used by the government in a manner that infringes on a reasonable expectation of privacy. If investigators can reasonably explain the necessity for electronic surveillance, the court will use its reason and judgment to evaluate the request. 76 notes