The Difference Between Reasonable Suspicion and Probable Cause

Reasonable Suspicion VS Probable Cause

Ahh “legalese.”

If you’re like most, you have a hard time understanding legal language.

No worries – I’ve got you covered.

What’s the difference when federal investigators or police say they have “reasonable suspicion” or “probable cause?”

Briefly, both help law enforcement decide when they should make an arrest. With probable cause, there’s concrete evidence of a crime. With reasonable suspicion, it only appears a crime may been committed. So investigators with reasonable suspicion use the term to justify further investigation when they observe suspicious behavior.

Why Do We Have Probable Cause and Reasonable Suspicion?

Our Constitution’s 4th Amendment protects you the citizen from “unreasonable searches and seizures.” And to get that warrant, they must have “probable cause.”

Prior to our Constitution, British officials could basically search the American colonists for whatever they wanted whenever they wanted. It forces law officials to have a search warrant. If you looked suspicious, or if they simply didn’t like you, they could ransack your entire home. So that’s where this whole idea of probable cause comes from.

Reasonable suspicion is a little more recent, stemming from a 1968 Supreme Court case. The ruling was law enforcement has a right to stop and briefly detain you if, based on their training and experience, there’s a good reason to think you’re engaging in criminal activity.

When Does Law Enforcement Need “Reasonable Suspicion” or “Probable Cause?”

It depends on what law enforcement’s goal is. If they want to stop and question you, they only need reasonable suspicion. They can search your body if they think you’re armed or if you present a threat of serious bodily harm.

If they decide to arrest you, or if they want to search you or obtain a search warrant, then they need “probable cause.”

One Example of Reasonable Suspicion and Probable Cause in Action

An example of reasonable suspicion is if you stumbled out of a bar and entered into your car. It’s possible you’re legally intoxicated, so if you try to drive away, a police officer who observed you enter the car might decide to approach you based on a reasonable suspicion of possible criminal activity.

He smells alcohol on your breath and notices you slur your speech. At this point, the officer now has probable cause to arrest you or conduct a further investigation.

Once probable cause kicks in, police don’t need to get a search warrant if time and circumstances dictate action is necessary. For example, it makes no sense for officers to let you drive home drunk while they go get a search or arrest warrant.

Typically you then get a field sobriety test, which, if you refuse to perform or fail when you attempt to perform, gets you arrested. By the way, you don’t have to agree to perform those tests (but that’s a whole different blog post).

Wrapping It All Up

There’s a small distinction between reasonable suspicion and probable cause, but there’s a higher burden of proof needed to justify “probable cause.”