The intro to Metallica's The Black Album song Don't Tread on Me interpolates the melody of America. Leonard Bernstein composed that melody for the musical West Side Story.
In the album context, the reference is brief and appears at the beginning of the track. It is not a separate cover version of the full musical number, which is why the song remains credited as an original Metallica composition.
America is a song from West Side Story, where it appears as part of the musical's exploration of identity and life in New York. Bernstein's melody is widely recognizable, making the interpolation an understated musical reference.
Listeners sometimes identify the passage as a national anthem or patriotic tune because of its familiar shape. The relevant source, however, is Bernstein's musical-theater melody, not The Star-Spangled Banner or another national song.