Probable Cause : PC is information sufficient to warrant a neutral magistrate's belief that a violation of the law has been committed and that the person to be arrested probably committed the violation; and as to a search, that the specific item(s) to be searched for are connected to criminal activities and that those items will probably be found in the place to be searched.

Question - Explain how the Supreme Court's reasoning regarding Probable Cause is different in these two cases: Spinelli v. United Statesand Illinois v. Gates.

Spinelli v. United States - Decision

Did the affidavit included in the warrant application afford probable cause sufficient to issue the search warrant?

No. The informant's tip, even when corroborated with the FBI's observations from their surveillance, was not sufficient to provide a basis for a finding probable cause when using the two-pronged test set forth in Aguilar v. Texas, 378 U.S. 108 (1964). (Abstract prepared by Blaine Schmidt.)

Illinois v. Gates - Decision

Did the search of the Gates's home violate the Fourth and Fourteenth Amendments?

The Court found no constitutional violation and argued that the lower court misapplied the test for probable cause which the Court had announced in Spinelli v. United States (1969). Justice Rehnquist argued that an informant's veracity, reliability, and basis of knowledge are important in determining probable cause, but that those issues are intertwined and should not be rigidly applied. He argued that the "totality-of-the-circumstances" approach to probable cause was the correct one to glean from Spinelli, and that the law enforcement officials who obtained a warrant abided by it in this case.