Draper v. United States

Police use of informants to obtain information on criminal activity has become common practice in the United States since Draper. The Draper decision encouraged the use of paid informants by allowing police to use information obtained from such informants as the basis for making arrests as long as police take time to personally verify or corroborate the information to the extent possible. Draper also established a definition of "probable cause" based on common sense, rather than technical rules, a definition still in use in the 1990s.