ILLINOIS v. GATES 462 U.S. 213 (1983)

This decision revived pre-warren court law of the fourth amendment concerning search warrants issued on informants ' tips. Justice william h. rehnquist for a six-member majority declared, "we … abandon the "two pronged test' established by our decisions in Aguilar and Spinelli. In its place we reaffirm the totality of circumstances analysis that traditionally had informed probable cause determination." In aguilar v. texas (1962) the Court had developed a test to govern a magistrate's probable cause hearing to determine whether a warrant should issue. Although hearsay information (an informer's tip not reflecting the personal knowledge of the police) may underlie an officer's affadavit for a warrant, the officer must also explain his belief that the informant is trustworthy or that his information is reliable. spinelli v. united states (1969) made the magistrate's hearing a mini-trial controlled by strict rules of evidence; the Court insisted on a degree of corroboration that proved the truthfulness of a tip apart from any evidence that might subsequently verify it. In effect the Court had escalated the constitutional requirement of probable cause to reasonably certain cause in order to insure that a magistrate could evaluate all facts and allegations for himself. Aguilar-Spinelli meant that although the police secured a warrant based on a tip and their search uncovered evidence of crime, that evidence could be suppressed and a conviction set aside if a court later decided that the magistrate should not have issued the warrant. In Illinois v. Gates Rehnquist recalled that probable cause is founded on practical, nontechnical considerations and that magistrates should apply flexible standards based on all circumstances rather than on a rigid set of rules. Justice william j. brennan, dissenting, declared that the majority opinion reflected "an overly permissive attitude towards police practices" contrary to Fourth Amendment rights.

Leonard W. Levy
(1986)