Which Wild West character does Paul Newman play in the 1958 film 'The Left Handed Gun'?

'The Left Handed Gun' is a 1958 American western film and the film directorial debut of Arthur Penn, starring Paul Newman as Billy the Kid and John Dehner as Pat Garrett.

The screenplay was written by Leslie Stevens from a teleplay by Gore Vidal, which he wrote for the television series 'The Philco-Goodyear Television Playhouse 1955' episode "The Death of Billy the Kid", in which Newman also played the title character. Vidal revisited and revised the material in 1989 with a TV-movie entitled 'Billy the Kid'. The title refers to the belief that Billy the Kid was left handed, and he shoots left handed in the film, though it is possible that this was a false conclusion drawn from a reversed photograph. The film attempts to portray Billy the Kid as a misunderstood youth who got mixed up in a cattle war and was dragged down by the hostile population of New Mexico.