'Appomattox': A superb night at the opera.

Something important happened at the Kennedy Center on Saturday night, and it was an opera called "Appomattox." Another opera of that name, by Philip Glass and Christopher Hampton, had its world premiere in San Francisco in 2007. The opera that the Washington National Opera opened on Saturday is also called "Appomattox," and is also by Glass and Hampton, but it's a complete revision of the first opera, with an entirely new second act. And although I didn't see the opera in San Francisco, I can sa...