Joan showed me this article in the latest New Yorker about George Gershwin. The piece, by Claudia Roth Pierpont seems to have been occasioned by the publication of The George Gershwin Reader, by John Andrew Johnson and Robert Wyatt.
Gershwin was classically trained, and aspired to be accepted by the musical establishment. He was also, of course, a student and lover of jazz. He worked to synthesize jazz into the symphonic form in compositions like Rhapsody in Blue. His writing makes it clear that he regarded jazz as an emerging art form, essentially American in its voice.
Like so many other "cross-over" or "fusion" artists before and since, Gershwin's work inspired vehement debate, and was often derided by purists from both sides: classical experts didn't consider it serious, and had serious misgivings about giving African American music a place. Black jazz musicians felt he had stolen, then "sanitized" their music, to make it acceptable to white audiences. This latter reaction is certainly reminiscent of more modern reaction to Elvis and The Beatles.
The controversy around Gershwin's work reached a crescendo (sorry, couldn't help myself) with the debut of Porgy and Bess, his last major work and magnum opus. Musical and racial criticisms turned ugly. Gershwin was apparently devastated, and died soon afterwards, feeling much of his life work had been rejected.
Gershwin's attempt to establish a uniquely American music ultimately failed. As Pierpont points out, by the mid-twenties, the jazz and symphonic traditions had begun to pull apart, creating a rift that lasted for decades, perhaps even until today.
Thanks to aworks for the useful links!