John Adams’s The Death of Klinghoffer opened at the Metropolitan Opera Monday night amid angry protests. The opera is based on the real-life, 1985 hijacking of a cruise-ship by Palestinian terrorists and their brutal killing of Leon Klinghoffer, a wheelchair-bound, 69-year-old American Jew. Inside Lincoln Center, the opera opened with paired choruses—a tense Chorus of Exiled Palestinians and a mournful Chorus of Exiled Jews—while outside, demonstrators shouted, somewhat less mellifluously, “Terror is not art!”

Morton Klein, president of the right-wing Zionist Organization of America, called Klinghoffer an “Operatic Kristallnacht” (I imagine anti-Semitic, glass-shattering high C’s). Truthfully, I do not know if the opera offers “a distorted view of history,” as former New York City Mayor Rudolph Giuliani claimed, or if “It’s required for the Met to do the piece,” as a supporter countered. But the strident moralism of both sides drowns out the quieter sounds of tickets being sold and seats filled. In fact, protests are good business for the Met, and scandal is central to the economy of high culture.

Just look at Amazon, where (as of this moment) a DVD of The Death of Klinghoffer is the second best seller in “Performing Arts,” wedged between “Annie” and a Fleetwood Mac concert film. Commercially, mass DVD sales are heady territory for high art; the only other opera in the top ten is haunted by Andrew Lloyd Webber’s déclassé phantom. This will be welcome news to the financially beleaguered Met, which faces declining ticket sales and depends heavily upon online donations. The Giuliani-themed fundraising emails, of course, all but write themselves.

Nor are the benefits to the Met only financial. There is considerable prestige in being attacked. Cancelling world broadcasts of the opera’s limited run, in a compromise deal with the Anti-Defamation League, will not cost the Met much. Rather, since smaller companies balk at the controversial Klinghoffer, the Met effectively secures—and publicizes—its monopoly on edgy, provocative fare. More broadly, the Klinghoffer uproar satisfies one of modern art’s central myths, in which the quality of a work correlates with the opposition it arouses among the vulgar. The riot that accompanied the Paris premiere of the ballet The Rite of Spring gave Stravinsky’s polytonality its artistic bonafides. Censoring Ulysses certified Joyce a prophet. Movies may garner awards, but high art requires scandal.

Even as the Met defines itself as “aesthetic” against the “political” masses (an editorial in The New York Times trumpets the “principle of artistic freedom in a world rife with political pressures”), it reinvigorates itself on its critics’ base passions. Somehow, it is the censors who have the deepest faith in art’s power. Artists, watching their elite, highly technical, and difficult crafts fade into irrelevance, may well envy their censors’ naiveté. Plato thinks poetry will corrupt your soul, but at least he thinks poetry makes something happen. Giuliani and Klein’s rhetorical bombast embolden the opera’s defenders, as when director Tom Morris, in a rousing defense of Klinghoffer, says the opera “reminds of what great works of art can do, and what great works of art are for.” No, it is the louts who remind us what art is for: épater la bourgeoisie. And of course, the bourgeoisie loves to be scandalized; it is better than being bored.

This whole dynamic should be familiar by now. Consider the 1999 Brooklyn Museum “Sensation” exhibit, over which then-mayor Giuliani threatened to evict the museum from its premises, and to which the Klinghoffer fight has inevitably been compared. The gallery was packed. Oglers were attracted less by Damien Hirst's formaldehyde-preserved shark or Chris Ofili's Virgin Mary with elephant feces than by the zoological spectacle of a boorish Giuliani and his reactionary attack dogs.

Similarly, University of Pennsylvania Professor James English, in a very canny book on literary prizes, shows how useful scandals have been to, for instance, the Booker prize. It is not just that they brought excitement and television-cameras to the award ceremony. The prizes’ banal boosterism allows condemnatory critics to rehearse publicly the value of pure, rarified art, an ideal that, in turn, bolsters the purpose of the prize. Scandals are how “symbolic capital” (to use French sociologist Pierre Bourdieu’s term) gets made.

So Kulturkampf has always been great publicity, (as it is for the Zionist Organization of America, which is also, in its own way, a floundering opera company). And acrimonious criticism often feeds high art’s prestige. Maybe if we acknowledged how useful protestors are to the Met, it would defang both sides’ self-righteousness. Because ultimately, the discordant notes from outside Lincoln Center are not interruptions. They are just part of the show.