The opening of Metallica's “Don't Tread on Me” interpolates a melody from which musical?

The opening of Metallica's “Don't Tread on Me” interpolates a melody from West Side Story.

The melody comes from “America,” a song associated with the stage musical and film West Side Story. “America” was composed by Leonard Bernstein, with lyrics by Stephen Sondheim for the musical's original production.

Metallica used the recognizable melodic idea as the introduction to “Don't Tread on Me,” creating a striking contrast between a Broadway-derived phrase and the band's heavy-metal arrangement. The song then moves into the album's guitar-driven sound.

Listeners sometimes identify the source simply as “America,” but the question asks for the musical that contains it. The precise answer is West Side Story, not the song title or its composer.