A battle is taking place in Israel that has nothing to do with the ongoing struggle between Israelis and Palestinians. This one is being waged among Jews themselves. But it is just as bitter as that other fight -- and just as pertinent, in its own way, to the question of Israel's present and future identity. How does a country function as the bifurcated entity Israel seems to want to be? How can it be both a democracy and a Jewish state?

At issue is the plan by the world-famous conductor Daniel Barenboim to lead his orchestra, the Berlin Staatskapelle, in a performance of the first act of "Die Walkure," by the 19th-century German composer Richard Wagner, at a state-sponsored music festival in Jerusalem on July 7. At any other music festival, anywhere else in the world, this would be an uncontroversial choice. Mr. Barenboim is a superstar, Wagner is an acknowledged musical genius, and Mr. Barenboim's reputation as a Wagner interpreter goes back a long way: He conducted "Tristan und Isolde" at Bayreuth as early as 1981. By strictly artistic criteria, this pairing should be a winner. And judging by the number of tickets reportedly sold already, a lot of concert-goers in Jerusalem agree.

But this is Israel, where nothing -- even art -- is ever that simple. Wagner, in particular, is not and probably never can be just another composer there. Nobody disputes his towering stature as a composer, but nobody seriously disputes his lifelong anti-Semitism either. A major theme of his operas is the ideal of racial purity; his stock embodiment of villainy is the materialistic Jew; and his anti-Semitic views were spelled out with brutal clarity in his polemical writings, notably 1851's "Jewishness in Music."