By now, a production of John Adams’s opera The Death of Klinghoffer presumes its own opposition . At the Teatro del Maggio Musicale in Florence last month, however, the terms of that opposition had shifted: the protesters weren’t the work’s habitual antagonists, demonstrating under the misapprehension that the opera is antisemitic or glorifies terrorism. They were activists from Firenze per la Palestina . Posters lining the walkway towards the opera house before the première of Luca Guadagnino’s new staging of Klinghoffer carried a photo of a woman in Gaza dwarfed by a pile of rubble, captioned (in Italian): ‘Let’s not forget the real “show” happening now.’ ‘We have to talk now about genocide, not about Palestinians as terrorists,’ one of the demonstrators said, though she had no issue with the opera or its libretto in principle. ‘The point is that nobody in mainstream art is taking a clear position on what’s happening,’ added another.…