Sine Qua Non

The term sine qua non is translated from Latin to mean “without which it could not be.” For example, sine qua non would apply to a situation wherein a child found his father’s gun in an unlocked cabinet and injured himself. The father, who left the gun cabinet unlocked, was the sine qua non of the injury that his child ultimately suffered — because had he not left the cabinet unlocked, the injury couldn’t have happened. To explore this concept, consider the following sine qua non definition.

Definition of Sine Qua Non


  1. Translated from Latin to mean “without which, nothing” to describe a situation that could not have happened without some condition having first been met.



Sine Qua Non Example Involving a Search and Seizure

An example of sine qua non can be found in the case of Ohio v. Robinette, which was heard by the U.S. Supreme Court in 1996. Here, Robert Robinette was pulled over for speeding by a deputy sheriff. After returning Robinette’s driver’s license and giving him a verbal warning over his speed, the deputy asked Robinette if he had any contraband in his car. Robinette denied this and consented to a search.

During the search, the deputy discovered marijuana and a single pill that would later be identified as ecstasy. A trial court convicted Robinette on charges of drug possession. Robinette appealed the decision to the Ohio Court of Appeals. The Court reversed Robinette’s conviction, ruling that the search resulted from an illegal detention sine qua non. The State appealed, but the Ohio Supreme Court upheld the decision. Further, the Court suggested that proper consent could only be given if Robinette knew that he was otherwise legally allowed to leave.

The U.S. Supreme Court agreed to hear the case and ultimately reversed the lower court. Here, the Court argued that the Fourth Amendment did not require police officers to inform people when they were free to go. On that note, this is not a requirement that must be met before the search can be considered voluntary. In their decision, the Court wrote:

“The Fourth Amendment does not require that a lawfully seized defendant be advised that he is ‘free to go’ before his consent to search will be recognized as voluntary. The Amendment’s touchstone is reasonableness, which is measured in objective terms by examining the totality of the circumstances. In applying this test, the Court has consistently eschewed bright-line rules, instead emphasizing the fact-specific nature of the reasonableness inquiry. Indeed, in rejecting a per se rule very similar to one adopted below, this Court has held that the voluntariness of a consent to search is a question of fact to be determined from all the circumstances. (Citation omitted) The Ohio Supreme Court erred in holding otherwise. It would be unrealistic to require the police to always inform detainees that they are free to go before a consent to search may be deemed voluntary.”