Illinois v. Gates1 was the most eagerly awaited constitutional-criminal procedure case of the 1982 Term. I think it fair to say, however, that it was awaited a good deal more eagerly by law enforcement officials and the Americans for Effective Law Enforcement than by defense lawyers and the American Civil Liberties Union. As it turned out, of course, the Gates Court, to the disappointment of many, did not reach the question whether the exclusionary rule in search and seizure cases should be modified so as not to require the exclusion of evidence obtained in violation of the fourth amendment when it is obtained in the "good faith" belief or "reasonable belief" that the challenged search or seizure was consistent with the fourth amendment. 2 Nevertheless, the Gates decision is important in its own right for it substantially dismantled the prevailing analytical structure for determining probable cause-the so-called "two-pronged test." 3 How much difference the Gates decision will make in the operation of the warrant procedure, and whether it signals the abandonment of the "two-pronged test" in warrantless as well as warrant cases, remains to be seen. How Gates' soft standard for upholding search warrants (and perhaps warrantless searches and seizures as well) will affect the proposal to adopt a "good faith" or "reasonable belief" exception to the exclusionary rule also remains to be seen. I believe Gates has an important bearing on this issue. I think its emphasis on the practical, flexible, and fluid nature of the "probable cause" standard substantially weakens the case for a "good faith" or "reasonable belief" test generally. Moreover, I think the Gates case totally obviates the need for such a test, if there ever was one, in the warrant context. A "good faith" or "reasonable belief" test by any other name is still a "good faith" or "reasonable belief" test, and as I read Gates the Court essentially adopted such a test in the warrant context.
Kamisar, Yale. "Gates, 'Probable Cause', 'Good Faith', and Beyond." Iowa L. Rev. 69 (1984): 551-615.