Bernstein's belief in a developing American musical vernacular wasn't limited to the symphony hall, either; he believed it was coming in theater as well. A chapter of Bernstein's book The Joy of Music briefly traces the development of musical comedy in America up to the point where George Gershwin arrived on the scene, and another chapter from the same book has Bernstein mourning the titanic loss to American music that Gershwin died so early when it seemed as if he was about to move into the most profound part of his career, after Porgy and Bess. For Bernstein, American musical comedy arose from the European operatic tradition just as American symphonic music had, with German singspiels and French operettas providing the templates.
So with West Side Story, Bernstein was trying to move the needle in the direction that Gershwin had been pushing at the time of his death. Did he succeed? I don't know, but perhaps it is easier to see the direction the musical theater took, away from individual songs and into more complete works. Hence today's featured piece, the Symphonic Dances from West Side Story, is comprised of a number of extracts from the show, arranged together to form the backbone of a ballet that could, in twenty-five minutes or so, roughly sketch out the action of the three-hour show. Bernstein didn't just stitch together a collection of numbers and call it a piece. The Dances are very much their own work with their own formal demands and their own sense of drama. The themes are not arranged in the exact sequence that they appear in the show, either; Bernstein was less about a "greatest hits" type of thing (obviously, perhaps, given that "I Feel Pretty" and "Tonight," to name just two of the show's most popular numbers, are not reference in the Dances) than about the creation of a single work that exists on its own. This he does, quite marvelously.
Here are the Symphonic Dances from West Side Story by Leonard Bernstein. In this performance, recorded at the BBC Proms in 2007, Gustavo Dudamel conducts the Simon Bolivar Youth Orchestra of Venezuela. This match of conductor and orchestra is responsible for some utterly amazing musicmaking, by the way.