What must law enforcement have to perform an investigative stop according to Terry v. Ohio?

In the context of Terry v. Ohio, law enforcement is required to have reasonable suspicion of a law violation to conduct an investigative stop, which is often referred to as a "Terry stop." This legal standard is lower than probable cause, which is typically necessary for an arrest or a search warrant.

Reasonable suspicion is based on specific and articulable facts that suggest criminal activity is afoot. This allows officers to make a brief stop and engage a person in conversation to confirm or dispel their suspicions without necessarily having to meet the higher threshold of probable cause. The objective is to balance the need for effective law enforcement with individuals' rights against unreasonable searches and seizures.

In this case, the other options do not meet the legal threshold established by the Supreme Court in Terry v. Ohio for conducting an investigative stop. Probable cause is necessary for arrests or obtaining search warrants, while clear evidence of wrongdoing and witness testimony are not requisite conditions for initiating a stop. Thus, the requirement of reasonable suspicion is fundamental to upholding the law while respecting individual liberties.