What is Probable Cause?
The general legal standard for probable cause is a belief backed by a reasonable foundation that a crime may have been committed. An inability to meet this level of concrete evidence classifies certain police responses as unlawful.
Legal History
Historically, a “two-pronged test” determined the ability of an officer to make an arrest under grounds of probable cause. This original criteria called for both knowing where informant tips came from and proving the informant was either credible or reliable, making it very difficult to use tips from anonymous sources as grounds for police action. However, in 1983, the SCOTUS case Illinois v. Gates loosened the requirements of this test and allowed for other evidence or circumstances to serve as sufficient proof for probable cause.
What is Reasonable Articulable Suspicion?
Reasonable articulable suspicion is a looser standard for police to take action against potential threats. Terry v. Ohio first established this idea that if “a police officer observes unusual conduct which leads him reasonably to conclude… that there is criminal activity afoot” they are permitted to “conduct a carefully limited search of the outer clothing”. The term “stop and frisk” describes this brief pat down process. A key concept from this case is that a practical person identifying a potential threat, beyond using pure conjecture, warrants reasonable suspicion.
Legal History
Various other SCOTUS rulings have more clearly defined the bounds of reasonable suspicion in all of its nuances. United States v. Arvizu loosened the standard of what is considered enough evidence for reasonable suspicion, allowing many seemingly insignificant observations to be combined to form a multifaceted hypothesis about possible danger. Furthermore, Illinois v. Wardlow established that flight from the police is sufficient reason to perform a pat down.
Permitted Law Enforcement Responses
Comparing the criteria for probable cause and reasonable suspicion, probable cause generally requires more objective evidence and reasoning. A simple observation of various questionable behaviors or circumstances achieves the criteria for reasonable articulable suspicion. However, the main distinction between these concepts are the actions that police can take under each circumstance. As stated earlier, reasonable articulable suspicion permits for brief detaining and basic pat-downs. Probable cause allows for all of these in addition to allowing for searches and sometimes arrests.
Important Takeaways
By imagining probable cause and reasonable articulable suspicion on a spectrum of police response, “cause” is just one level above “suspicion” in terms of force. Though probable cause and reasonable suspicion are both necessary for addressing potentially dangerous situations, confusing them is detrimental to our personal rights. It is important to be aware of your rights during any law enforcement encounter.