Terry v. Ohio · ¶55

In other words, police officers up to today have been permitted to effect arrests or searches without warrants only when the facts within their personal knowledge would satisfy the constitutional standard of probable cause. At the time of their “seizure” without a warrant they must possess facts concerning the person arrested that would have satisfied a magistrate that “probable cause” was indeed present. The term “probable cause” rings a bell of certainty that is not sounded by phrases such as “reasonable suspicion.” Moreover, the meaning of “probable cause” is deeply imbedded in our constitutional history. As we stated in Henry v. United States, 361 U. S. 98, 100-102:

U. S. Reports, bound volume
U. S. Reports, volume 392, at 1 (Library of Congress) · transcription: Caselaw Access Project
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