What must a law enforcement officer have to lawfully stop a motor vehicle?

To lawfully stop a motor vehicle, a law enforcement officer must have reasonable articulable suspicion. This standard requires that the officer have specific facts or circumstances that lead them to believe that a crime may be occurring or that the individual is involved in criminal activity. It's a lower threshold than probable cause and allows officers to take action based on observed behavior or specific information.

Reasonable articulable suspicion is essential because it balances the need for police to enforce the law and prevent crime while also protecting individuals from arbitrary stops. If an officer can clearly articulate the reasons behind the stop, such as erratic driving or a violation of traffic laws, they are acting within legal guidelines, ensuring that citizens' rights are respected.

The other standards, such as probable cause, proof beyond a reasonable doubt, and preponderance of the evidence, are applicable in different legal contexts. Probable cause is needed for arrests or search warrants, while proof beyond a reasonable doubt is the standard used in criminal trials to determine guilt. Preponderance of the evidence is typically used in civil cases to establish liability. Thus, having reasonable articulable suspicion is the correct and necessary condition for a lawful traffic stop.