In the U.S., it is unconstitutional for a police officer to demand identification from a citizen who is not breaking any laws or causing a disturbance. However, in some states, an officer with reasonable suspicion to believe you may have been involved in a crime can stop you and demand ID.
Reasonable suspicion involves more than just some arbitrary reasoning, a gut feeling, or a “hunch.” Before police may lawfully detain you, they must have specific, rational reasons to believe that you have committed—or are about to commit—a crime.
Reasonable suspicion only authorizes police officers to take specific, limited actions. For instance, an officer cannot place you under arrest based solely on reasonable suspicion. Before making an arrest, police must have probable cause—a higher standard of justification than reasonable suspicion.
With reasonable suspicion, a law enforcement agent may briefly detain you and ask you questions. In states with stop and identify laws, the agent also may ask to see your ID. Further, if the agent has reason to believe that you may be armed, he or she may conduct an over-the-clothes pat-down (also known as a “frisk”) to check for weapons.
Sometimes, police will stop you and ask you questions without actually detaining you. If you are unsure whether or not you are being detained by a police officer, you can politely ask: “Officer, am I being detained, or am I free to go?”