TEMPERS RARELY flare as hot about musical matters as they do about the work of Richard Wagner.

The 21st century still brings headlines about the family feuds of his heirs as they struggle with each other to control the festival the composer founded in Bayreuth, Bavaria, to celebrate and perpetuate his work.

In the summer of 2001 there was a scandal when conductor Daniel Barenboim broke the taboo on performing Wagner in Israel. He played the prelude to Tristan und Isolde as an encore at a concert with the Berlin Staatskapelle in Jerusalem.

Barenboim, who is an Israeli citizen, had wanted to conduct part of the opera Die Walküre, but was persuaded to turn instead to Schumann and Stravinsky. He got the idea of Wagner as an encore, he said, when he heard a mobile-phone ringtone of The Ride of the Valkyries (from the opera he had been dissuaded from conducting) at a press conference he gave in Jerusalem.

And when, at the end of the concert, he announced that the Berlin orchestra would play Wagner as their second encore, there was a prolonged discussion, much protest, and dozens of departures from the audience, all followed by a warm reception for the actual performance.

The fallout reverberated around the world. Barenboim was denounced by then Israeli prime minister Ariel Sharon. Ehud Olmert, then the mayor of Jerusalem, accused the conductor of being “brazen, arrogant, uncivilised and insensitive” and said the city would have to reconsider its future relationship with him. Ephraim Zuroff of the Simon Wiesenthal Centre called his action “cultural rape” and said, “That’s exactly what he did, he tried to seduce the Israeli public. The Israeli public refused, he raped us.”

Wagner, of course, was a notorious anti-Semite, and his music was exploited for propaganda purposes by the Nazis. Google the names Hitler and Wagner and you’ll be told there are more than eight million relevant hits. This, while lower than the score for Hitler and Goebbels, is a lot more than the pairings of the dictator with Goering or Himmler.

A published conversation between Barenboim and cultural critic Edward Said outlines the conductor’s balancing act. As a person, Barenboim explained, Wagner “is absolutely appalling, despicable, and, in a way, very difficult to put together with the music he wrote, which so often has exactly the opposite kind of feelings. It is noble, generous . . . The fact remains that he was a monstrous anti-Semite. How we would look at the monstrous anti-Semitism without the Nazis, I don’t know. One thing I do know is that they, the Nazis, used, misused, and abused Wagner’s ideas or thoughts – I think this has to be said – beyond what he might have had in mind . . .

“It also needs to be said for clarity’s sake that, in the operas themselves, there is not one Jewish character. There is not one anti-Semitic remark. There is nothing in any one of the 10 great operas of Wagner even remotely approaching a character like Shylock.

“That you can interpret Mime or Beckmesser in a certain anti-Semitic way (in the same way, you can also interpret The Flying Dutchman as the errant Jew), this is a question that speaks not about Wagner, but about our imagination and how our imagination is developed, coming into contact with those works.”

THE REASON we pay attention to Wagner, of course, is his music. His revolutionary political views, the extravagance of his life-style, his exploitation of the patronage of Ludwig II of Bavaria, his predatory sexual appetite all add colour to the many biographies and studies that have been penned over the years. But it’s the music that’s the thing.

Even his grandiose ideas about the Gesamtkunstwerk – the total work of art that would embrace music, dance, poetry, architecture, sculpture and painting – pale into insignificance beside the music itself.

The cathedral he succeeded in building for his work, the Festspielhaus in Bayreuth – unique in its acoustic and layout, and a place of pilgrimage for the Wagner faithful – has long since abandoned the restrictive stage practices that were perpetuated in the decades after his death, when his widow Cosima was in charge of the festival. And voiceless, wordless performances of favourite moments from the operas, once a staple of orchestral concerts, still make their appearance in concert programmes to this day.

During the composer’s lifetime the description “Music of the Future” was used both as encomium and pillory. But the immediate future of German opera after his death was dark. He had no direct successor. In 1894, the Viennese critic Eduard Hanslick considered the assertion by Wagner’s son Siegfried that Humperdinck’s Hansel and Gretel was the most important opera since Parsifal. “In other words,” asked Hanslick, “the best in full 12 years?” This was, he said, “An irritating pronouncement, and the worst of it is – that it is true.”

Yet Wagner’s influence has been remarkably pervasive. The development of the full glory of the late-romantic symphony orchestra and the early 20th-century erosion of the tonal system that had served music for hundreds of years are hard to imagine without him. And it’s not easy to see where Mahler, Strauss and Schoenberg might have headed in his absence.

Opera lovers and concert goers, of course, don’t have to worry about historical significance, or appreciate how influences grew and spread. They vote with their wallets, and even the greatest opera houses in the world turn to Wagner in their hour of need. When the Royal Opera in London was out of a home to allow its base in Covent Garden to be redeveloped, it turned to concert performances of the four operas of the Ring. The only complete Ring in Ireland in living memory was a concert performance by the National Youth Orchestra under Alexander Anissimov (given in Limerick and Birmingham in 2000), and it managed to spawn a Wagner society here that remains active today.

But Wagner has had only a poor showing here in Ireland. Wide Open Opera’s Tristan & Isolde at the Bord Gáis Energy Theatre is the first production here since 1963. The now defunct Opera Ireland’s only approach to the Ring was a concert performance of Das Rheingold in 2009 – strange as it may seem, the company mounted more productions of Verdi’s Rigoletto alone than it did of all of Wagner’s operas.

This is a shameful state of affairs and the public, I suspect, is at a double loss. There’s the loss of the direct experience of Wagner in the theatre. And there’s a consequential loss from the lack of Irish musicians’ and particularly composers’ exposure to Wagner in the theatre. Wagner commanded a kind of subterranean, or if you like, a seismic power that’s not readily found elsewhere. It’s got both a crudeness and a sophistication behind it which some people find simply thrilling and which others find repugnant. It wants to take you over, and you either have to give in or prepare for a long struggle. And you can’t get the full experience of this from a CD or a DVD.

For years now, I haven’t been able to get out of my head the idea that composers growing up in Ireland are effectively being deprived of an essential element of their education, a visceral contact with some of the most extravagant – or, if you prefer, outlandish – aspirations that any composer of the highest genius ever brought to fulfilment.

Tristan und Isolde is at the Bord Gáis Energy Theatre on Sunday (5pm), Wednesday (6pm), and Saturday, September 7th (5pm). bordgaisenergytheatre.ie