Related cases

The Supreme Court decision Illinois v. Gates (1983) lowered the threshold of probable cause by ruling that a "substantial chance" or "fair probability" of criminal activity could establish probable cause. A better-than-even chance is not required.

The decision in Terry v. Ohio (1968) established that some brief seizures may be made without probable cause. If an officer has a reasonable suspicion that a crime has been committed or will soon be committed, that officer may briefly detain a suspect to frisk him for weapons and question him. This is known as a "Terry stop."

In United States v. Matlock, 415 U. S. 164 (1974), the Court announced the "co-occupant consent rule" which permits one resident to consent in the co-occupant's absence. The case established that an officer who makes a search with a reasonable belief that the search was consented to by a resident does not have to provide a probable cause for the