What is the exclusionary rule in the context of search warrants?

The exclusionary rule is a judicially created remedy designed to safeguard Fourth Amendment rights. (United States v. Leon (1984) 468 U.S. 897, 907.) The rule was designed to deter police misconduct, and does not apply to objectively reasonable law enforcement activity. (Id. at pp. 916, 919.) The exclusionary rule does not bar the use of evidence obtained by officers acting in reliance on a search warrant issued by a detached and neutral magistrate but ultimately found to be unsupported by probable cause unless the affidavit is " 'so lacking in indicia of probable cause as to render official belief in its existence entirely unreasonable.' " (Id. at pp. 900, 923.) " '[A] warrant issued by a magistrate normally suffices to establish' that a law enforcement officer has 'acted in good faith in conducting the search.' " (Id. at p. 922.) When evidence is obtained pursuant to a warrant later found to lack probable cause, suppression is determined on a case-by-case basis, and "only in those unusual cases in which exclusion will further the purposes of the exclusionary rule." (Id. at p. 918.)