Robbins: What is probable cause? |

Robbins: What is probable cause?

Before the Minneapolis cops were arrested in the George Floyd killing, there was, rightly, a hue and cry about “probable cause.” Pundits, protesters and others of good moral conscience held, in one guise or another, “You saw the video yourself! Isn’t that enough to charge? If the video does not amount to probable cause, then what does?!”


Before we get on with the specific issue, a little context is in order.

The structure of our form of government is one of push and pull, give and take, yin and yang. OK, that’s not exactly what’s written in the Constitution; in fact, a word search turns up neither yin nor its fraternal twin brother, yang. But what I mean by this is that the Constitution giveth and the Constitution taketh. There are both rights and obligations of citizenship. There are starts and stops and cautions.

The Fourth Amendment provides that, “The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no warrants shall issue, but upon probable cause, supported by oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized.”

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So there they are, towards the back end of the middle; the words “probable cause.” But what exactly do they mean?

Let’s define. 

Adaptation and extrapolation

“Probable cause” is the Fourth Amendment requirement that must usually be met before police make an arrest, conduct a search, or receive a warrant. Courts generally find that probable cause exists when there is a reasonable basis for believing that a crime may have been committed (for an arrest) or when evidence of the crime is present in the place to be searched (for a search).  

Under some circumstances, probable cause may be dispensed with and a warrantless search or seizure may be conducted. Persons arrested without a warrant must be promptly brought before the court to ensure that their Fourth Amendment rights have not been violated and there is a reasonable basis for a determination of probable cause.

Although the Fourth Amendment states that “no warrants shall issue, but upon probable cause,” like much of the Constitution, the blanks are meant to be filled in by circumstance and judicial interpretation. This is not by accident. The Founding Fathers intentionally painted the Constitution in broad strokes, understanding that time and circumstance would require adaptation and extrapolation.

The Fourth Amendment simply does not specify of what “probable cause” actually consists.  

On several occasions, the Supreme Court has tried to fill in the dots and clarify the meaning, recognizing that the concept that is — by design — imprecise, fluid and dependent on context and the nearly infinite precise circumstances that may present themselves.

In Illinois v. Gates, a 1983 case, the Supremes adopted a flexible approach, viewing probable cause as a “practical, non-technical” standard that calls upon the “factual and practical considerations of everyday life on which reasonable and prudent men […] act.” Hmmm; not much guidance there.  Essentially, the Gates court embraced an “I know it when I see it” approach.

Courts have often adopted a more expansive view of probable cause when the alleged offense is serious.

In the context of arrest, the Fourth Amendment requires probable cause even when the arrest is made pursuant to an arrest warrant. Whether or not probable cause exists depends on the totality of the circumstances, meaning everything that the arresting officers know or reasonably believe at the time the arrest is made. However, “reasonableness” is a chameleon colored by the specific circumstances.

A lack of probable cause will render a warrantless arrest invalid, and any evidence resulting from that arrest will be suppressed. This “exclusionary rule” will bar the introduction of evidence that flowed from the arrest, including physical evidence, inculpatory statements or confessions.

In the circumstance of law enforcement searches, probable cause exists when there is a fair probability that a search will result in evidence of a crime being discovered. In the case of a search pursuant to a warrant, an affidavit must support the warrant by indicating on what basis probable cause exists. A judge may issue a search warrant if the affidavit in support of the warrant offers sufficient credible information to establish probable cause. 

For a warrantless search, probable cause can be established by in-court testimony after the search.

Reasonableness and fairness

The protections against unreasonable searches and seizures codified in the Fourth Amendment directly reflect the fledgling American nation shrugging off the bounds of what it saw as British repression. If the government was to act against a citizen, it would have to do so pursuant to established rules, concepts of reasonableness, and fairness.

Probable cause is a check against state zealotry and police aggression and makes each of us more secure in his person and his home.

In Minneapolis, the video spoke for itself. 

Was there probable cause? 

If you know when you see it, well, duh.

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