Composer David Diamond (1915–2005) was always an outspoken advocate of traditional musical ideals—expression, communication, craftsmanship—during decades of questioning experimentation from American music’s avant-garde wing. His steadfastness of purpose was sorely necessary during the travails of his opera The Noblest Game. Scheduled for a New York City Opera production in 1975, it was canceled due to a change in leadership at that company; re-slated and re-canceled in 1995; and finally taken up by Diamond champion Gerard Schwarz, who programmed a suite of six arias for a 1998 Seattle Symphony concert. This too had to be canceled when the singer fell ill. So cross your fingers that nothing happens to soprano Jennifer Zetlan before, at last, next Thursday’s world premiere of the only fully orchestrated, performance-ready fragments of Diamond’s ill-fated opera, four decades after he began work. The libretto is by socialite and State Department official Katie Louchheim, who set her story in a milieu she knew well, the snake pit of Washington, D.C., politics. (The title may or may not be ironic.) Diamond juiced up the music for Louchheim’s heroine- with-a-past, Sabina, with a thrusting vocal line, plenty of high Bs, and—at one point in the score—a “bloodcurdling scream.” In fact, the whole thing sounds lurid enough to stand up next to Bartók’s over-the-top one-act Bluebeard’s Castle (the title nobleman’s seventh wife meets the ghosts of her six murdered predecessors) in a semi-staged production that uses gorgeous sculptural set pieces by Dale Chihuly. (Diamond accompanies Bartók only on Thursday; next Tuesday, Bluebeard is preceded by a piano concerto—another premiere—by Michael Hirsch.)