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."

Nor is this the whole, or even the main, problem. Many artists, including composers, have been anti-Semitic. More offensive to Jews than Wagner's reflexive anti-Semitism is his association with Nazism. Adolf Hitler not only admired Wagner's plangent, myth-heavy music, he venerated him as one of the spiritual fathers of National Socialism and made him the virtual musical symbol of the Third Reich. Understandably, there has been an informal ban on performances of Wagner's music in Israel since the nation's founding in 1948. The ban never needed formalizing, since the assumption was that no Jew in his right mind would ever want to perform or hear Wagner.

Until now. That assumption has been quietly challenged in recent years with Wagner excerpts being played occasionally on state-funded Israeli radio and in a brief public performance last year. But Mr. Barenboim's plan to conduct an entire act of "Die Walkure" in Jerusalem in July has really brought matters to a head. After the festival program was announced, outraged Israelis, including a number of Holocaust survivors, called on organizers to cancel the Wagner segment. Last week, the government and the Knesset formally asked them to reconsider proceeding. A furious public debate continues, as other Israelis argue for the right to perform and listen to whatever music they wish. Mr. Barenboim himself has eloquently defended his decision, pointing out that Wagner was posthumously misappropriated by the Nazis, that no one is being forced to attend the concert, and that it is on exactly this kind of issue that Israel "can and should define itself as a democracy."

It is possible to sympathize with some of the counterarguments here: for example, that even though Wagner was obviously not a Nazi himself (he died in 1883), Hitler was quite right to zero in on the link between the composer's grandiose visions and the grim "Gotterdammerung" of Nazism; or that a state-sponsored concert is freighted with implications -- of approval, of sanction even -- that a private event would not be.

But it is hard to argue against Mr. Barenboim's third point: that this case turns on the question of the kind of country Israel wants to be. In a democracy, cultural programs are neither dictated nor censored by the state. The ticket-buying public is free to express its approval or disapproval by either attending or staying away. If Israelis -- in any number -- want to hear Wagner, democratic norms require that they should be able to do so.

As Israel's fight for a secure place in the Middle East bogs down after yet another year of disappointments, the temptation to close ranks against anti-Jewish sentiment both past and present is understandable. But whether that occurs on a military, political or cultural front, the ramifications are likely to be antidemocratic. A case can be made that Israel's future in the region depends on its ability to shed its image as a semi-theocratic state. What better start could be made than by hosting Wagner in Jerusalem this summer?