Broadway is notoriously unappreciative of chance takers, but in recent years, at least, it has come to honor Sondheim's work with a regularity bordering on inevitability…. This year was no different: "A Little Night Music," his third show in three years, was named best musical, and Sondheim walked off with the Tony for best words and music.

Which is as it should be—and shouldn't. For the embarrassment of Tonys on Sondheim's mantelpiece also points up the embarrassing state into which the Broadway musical—America's great original contribution to the theater—has fallen. Once upon a time, the musical show was Broadway's brightest beacon to the world, sweeping from Catfish Row to Siam with passionate assurance, finding ballet in floating crap games and love in the garment industry. Once, it nurtured much of the best musical talent in the country, whether it belonged to a Russian Jewish immigrant...