Officer Samuel Huizar was working undercover in a drug investigation. While Huizar was beginning a negotiation to buy crack cocaine from a suspected drug dealer, Luis Robles (defendant) told the drug dealer that Huizar was an undercover policeman and to get away from Huizar. After Huizar told the suspect that he was not a police officer, Robles approached the suspect and repeated that Huizar was a police officer and that the suspect should leave. The suspect then ended the negotiation and fled. Robles was charged and convicted with obstructing an officer in the discharge of his duties. Robles appealed, alleging that the conviction violated his right to freedom of speech as guaranteed by the Constitution.