Probable Cause

Snippet 1: Probable Cause and the Constitution

In most contexts, PC refers to "political correctness"—the determination to avoid saying anything that might stereotype or insult someone on the basis of race, gender or ethnic history. But in the context of the law, the letters "PC" have an altogether different meaning. They serve to abbreviate the phrase probable cause, a term derived from the Fourth Amendment of the Constitution.

According to the Fourth Amendment, the police need probable cause in order to arrest someone not caught red-handed committing a crime. They need to be able to show the facts and events that would lead a sensible person to believe a crime is being, or about to be, committed by a specific person or persons. The same is true for search warrants. As any long-time Law and Order fan knows, police spend a good deal of time proving probable cause to judges. If the police can't show probable cause, they don't get search or arrest warrants . That's because the Fourth Amendment of the Constitution insists on the importance of probable cause:

"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."

Snippet 2: Probable Cause, Television Style

If you are still in doubt about the meaning of probable cause, this snippet of video from the TV show Hawaii 5-0 should be some help. Just remember, these are cops determining probable cause for the cameras, not a real-live court room.

Snippet 3: Probable Cause and the Supreme Court

Although the Constitution insists that search and arrest warrants cannot be issued without probable cause, it's not specific about what kinds of behavior or activity fall into that category. As Police Magazine has pointed out, the general vagueness in the wording has caused considerable confusion. In fact,so much confusion has arisen around probable cause that the Supreme Court has tried more than once to offer some guidelines. In 1949, it issued a decision that suggested probable cause required more common sense than technical training:

"In dealing with probable cause, we deal with probabilities. These are not technical; they are the factual and practical considerations of everyday life on which reasonable and prudent men, not legal technicians, act. Probable cause exists where the facts and circumstances within the officers' knowledge and of which they have reasonably trustworthy information are sufficient in themselves to warrant a man of reasonable caution in the belief that an offense has been or is being committed." (Brinegar v. U.S.)

Apparently, though, that decision did not clear up the confusion about how to determine probable cause. The court returned to the subject again with the most pointed explanation coming in 1983 in Illinois v. Gates. To counter lower court decisions that suggested there was a clear-cut check list for probable cause, the Supreme Court insisted that there was no totally precise way of determining probable cause. The determination would always be a matter of common sense and context.

"The evidence must be seen and weighed not in terms of library analysis by scholars, but as understood by those versed in the field of law enforcement. Probable cause is a fluid concept, turning on the assessment of probabilities in particular factual contexts-not readily, or even usefully, reduced to a neat set of legal rules." (Illinois v. Gates)

Last change made to this page: April 19, 2011