Massachusetts v. Upton

Last Term, in Illinois v. Gates, 462 U. S. 213 (1983), we held that the Fourth Amendment’s requirement of probable cause for the issuance of a warrant is to be applied, not according to a fixed and rigid formula, but rather in the light of the “totality of the circumstances” made known to the magistrate. We also emphasized that the task of a reviewing court is not to conduct a de novo determination of probable cause, but only to determine whether there is substantial evidence in the record supporting the magistrate’s decision to issue the warrant. In this case, the Supreme Judicial Court of…