“Don’t Tread on Me” from Metallica’s 1991 album interpolates Leonard Bernstein’s “America.”
The reference appears in the song’s introduction and comes from Bernstein’s music for West Side Story. “America” is one of the best-known numbers from that musical, which premiered on Broadway in 1957 with music by Bernstein and lyrics by Stephen Sondheim.
An interpolation incorporates recognizable musical material into a new composition without necessarily presenting it as a complete cover. In this case, Metallica used the melody as a brief opening element before moving into its own heavy-metal arrangement.
The song’s title and lyrics also connect with American patriotic imagery. Its title echoes the motto associated with the Gadsden flag, whose coiled snake appears on the Black Album cover. Listeners sometimes identify the introduction simply as “West Side Story,” but the specific Bernstein composition is “America.”