Probable cause is a legal standard used in the criminal justice system to determine whether law enforcement has sufficient reason to believe that a crime has been committed. It is the basis for obtaining search warrants, making arrests, and conducting searches. Essentially, it requires more than mere suspicion but less than the level of proof required for a conviction. In practice, probable cause is established through facts, evidence, or circumstances that would lead a reasonable person to conclude that a crime has occurred. This concept is crucial in protecting individuals' rights while allowing law enforcement to perform their duties effectively, ensuring a balance between public safety and personal freedoms.