The opening of Metallica's “Don't Tread on Me” quotes “America” from West Side Story.
The instrumental introduction uses an eight-bar phrase from “America,” a song associated with Leonard Bernstein's music for the 1957 musical. Metallica incorporated the phrase into the album track before moving into its own guitar-driven arrangement.
“Don't Tread on Me” appeared on Metallica's self-titled album and drew on American Revolutionary imagery, including the Gadsden flag's snake motto. The snake image also connects the song to the visual identity of The Black Album.
The musical reference is easy to confuse with other famous West Side Story songs such as “Tonight,” “Maria,” and “Somewhere.” Those songs are not the source of the opening phrase. “America” is the specific composition interpolated at the start of Metallica's track.