There is no "PC for the Stop"
Under Fourth Amendment case law, there are three distinct levels of interaction between police and citizens: (1) consensual encounters, (2) detentions, and (3) arrests. (U.S. v. Mendenhall) Determining which one is occurring at a given time requires looking at what officers have said and done to see what degree of restriction (if any) is placed on the person's liberty.
(1) If there is no restriction because police have neither said nor done anything that would have communicated to a reasonable, innocent person that he or she must submit to the encounter, any interaction is purely consensual and requires no justification. (INS v. Delgado)
(2) If the person's liberty is temporarily restricted by a police command, display of emergency lighting, physical restraint or other means that would have communicated to a reasonable, innocent person that he or she was not free to disregard the police and come or go at will, a detention has occurred, requiring reasonable suspicion that the person may be involved in criminal behavior. (Florida v. Bostick) The two most common kinds of detention are the pedestrian stop (Terry v. Ohio) and the vehicle stop. (U.S. v. Hensley)
(3) An arrest typically involves either telling the person he is under arrest, or taking him into physical custody—usually by cuffing and caging the person and transporting him to a police station or jail. (Kaupp v. Texas) The level of justification required for an arrest is probable cause, commonly abbreviated "PC." (Atwater v. City of Lago Vista, Texas)
From these principles, it should be clear that PC is not needed for a stop—only for an arrest. All the Fourth Amendment requires for a stop (detention) is reasonable suspicion. "Reasonable suspicion is a less demanding standard than probable cause." (Alabama v. White) "The police can stop and detain a person for investigative purposes if the officer has a reasonable suspicion, even if the officer lacks probable cause." (U.S. v. Sokolow)
When police officers speak or write or testify about their "PC for the stop," they are feeding the confusion of legal standards that may already be cloudy to some prosecutors, defense attorneys, and trial judges. A judge hearing a suppression motion and looking for PC for a stop may find that the stop was unjustified—even though there was reasonable suspicion to support it. Officers need not take on a higher burden than the law specifies, but that is exactly what the improper linking of detentions and PC accomplishes. So if you've developed the bad habit of trying to mix PC and stops, it's time to break that habit and speak with legal precision. Stops require only reasonable suspicion—not probable cause. "PC" and "stop" are immiscible. Don't try to mix them.
Miranda and "Not Free to Leave"
How this one got started is anybody's guess. Many officers, attorneys, and judges think the test for Miranda "custody" is to ask whether, at the time police interrogation occurred, the suspect was, or was not, "free to leave." This analytical mistake likely arose from careless mixing of the old test for a detention under U.S. v. Mendenhall (under which a person was detained when he was no longer free to leave) with the "custody" factor from the Miranda equation.
Miranda v. Arizona ruled that judges could not admit as evidence of guilt at trial a confession obtained by police custodial interrogation, unless the prosecutor showed that the inherent compulsion of this process had been neutralized by the now-familiar warning and waiver. The evidentiary prerequisites of warnings and waiver are triggered by the combination of "custody" and "interrogation." (Illinois v. Perkins)
In later decisions, the Supreme Court defined "custody" as "formal arrest or its functional equivalent." (Berkemer v. McCarty; California v. Beheler) Examples of the functional equivalent of formal arrest could be handcuffing and caging the suspect, pointing guns, or preventing the suspect from leaving the police station. (Orozco v. Texas) Miranda "custody" and Fourth Amendment "arrest" are not synonymous, because "custody" also includes detentions accomplished with arrest-like restraints; therefore, even though an officer may not have formally arrested a suspect, if the suspect is being subjected to the functional equivalent of arrest at the time of questioning, he is in "custody" for Miranda purposes.
But in the absence of arrest-like restraints or stationhouse settings, the mere fact that a suspect is being detained ("not free to leave") does not mean that he is in "custody." For example, during a pedestrian detention or a vehicle stop, the person being questioned is "not free to leave," but as long as he is not restricted by handcuffs, police-car cage or pointed firearms, he is not in Miranda "custody." The Supreme Court made this point in Berkemer, where a motorist stopped for suspected driving under the influence was questioned without warnings before being taken into custody:
"The comparatively non-threatening character of [pedestrian] detentions explains the absence of any suggestion in our opinions that Terry stops are subject to the dictates of Miranda. The similarly non-coercive aspect of ordinary traffic stops prompts us to hold that persons temporarily detained pursuant to such stops are not in custody for the purposes of Miranda." (Berkemer v. McCarty)
Although this passage from Berkemer made clear that Miranda does not apply merely because a person is detained ("not free to leave"), it was necessary for the Supreme Court to reverse the Pennsylvania Supreme Court on this very point four years later. In Pennsylvania v. Bruder, the commonwealth court had mistakenly ruled that Miranda applied at a car stop, because the driver was not free to leave. In a brief, four-paragraph decision, the U.S. Supreme Court reversed this ruling and repeated that temporary detentions lacking arrest-like restraints do not constitute "custody" for Miranda purposes.
If police officers, attorneys, and judges erroneously believed that Miranda required the exclusion of statements obtained without warnings and waiver at a time when the suspect was concededly not free to leave but not yet under formal arrest or its functional equivalent, crucial evidence of guilt could be needlessly lost. Miranda "custody" and "not free to leave" are immiscible. Don't try to mix them.
