A few scenes were filmed at the Ambassador Hotel in Los Angeles, the real-life location of the Robert F. Kennedy assassination, during its demolition. The wing of the hotel they were using hadn't been touched by the demolition crew yet, in order to preserve items from the pantry where Kennedy was shot.
It took Emilio Estevez seven years to get the movie made. At one point, he had such a case of writer's block that he only had 30 pages of the script and lied to people that he was working on it. His brother Charlie Sheen read the pages and convinced him to finish.
The scene of Sharon Stone's character cutting her husband's hair (played by William H. Macy) was not in the script. Stone was to pantomime cutting the hair, but she actually snipped his hair. Macy's visibly tense reaction to the haircut was real.
Anthony Hopkins plays a door man named John Casey in the film. In reality, there actually was a John Casey who served as door man at the Ambassador Hotel. At the end of the credits, it states, "'John Casey' is the name of an actual doorman at the Ambassador Hotel from 1928-1965. His portrayal in this film is not intended to reflect the actual facts of his life or legacy."
The trivia items below may give away important plot points.
The character of Jose, played by Freddy Rodríguez ultimately shakes Robert F. Kennedy's hand moments before Sirhan Sirhan shoots Kennedy. This is based on actual fact; Latino busboy Juan Romero was holding Kennedy's hand when the Senator was shot in the Ambassador Hotel. Both Romero and Jose cradle Kennedy's head and give him a rosary to hold.
When Senator Kennedy is assassinated, William (Elijah Wood) is shot in the head by a random bullet. This is a reference to how one of the five people wounded by Sirhan Sirhan's wild shots was hit in the head, miraculously surviving the wound.
According to writer/director Emilio Estevez, the actions of Dwayne (Nick Cannon) after Kennedy's assassination were based on how a young black man furiously threw a chair against the wall when told of Kennedy's being shot.