This week's visit by Hungarian Prime Minister Gordon Banjai is an excellent opportunity to focus on one of the most important and interesting cases of a Nazi war criminal who can still be brought to justice. I am referring to Dr. Sandor Kepiro, who served as a gendarmerie officer during World War II and was among the key organizers of the mass murder of at least 1,250, but probably as many as 3,000 men, women and children (mostly Jews, but also Serbs and Gypsies) in the Serbian city of Novi Sad on January 23, 1942. Until now, Israel has done relatively little to press Hungary to prosecute Kepiro, so Banjai's visit might well be the last opportunity of its kind for the government to send a clear-cut message to the Hungarians that their failure to bring Kepiro to justice is incomprehensible and unacceptable. The Kepiro case has special significance for several reasons. First and foremost is the scope of the massacre in Novi Sad, which was the largest single action of its kind against Jews in Serbia during the Holocaust, and besides the murders carried out by Hungarian troops in Kamenetz-Podolsk, was the worst case of the mass murder of civilians carried out by Hungarian forces during World War II. Another important point is that if Kepiro is brought to trial in Budapest, he will almost certainly be the first Hungarian Nazi collaborator to be prosecuted since the country became a democracy. Like all the post-communist states of Eastern Europe, Hungary conducted many trials of Nazi collaborators in the immediate aftermath of World War II, but none since the transition to democracy. This would be particularly significant in a country like Hungary, which is only beginning to honestly confront its crimes during the Holocaust, which included mass murder. THERE ARE ALSO several unique aspects to the Kepiro case which add to its significance. To the best of my knowledge, it is the only case of Holocaust crimes carried out by the forces of a country allied with Nazi Germany, in which the perpetrators were actually prosecuted by their own government in the course of World War II. In December 1943, the 15 officers who organized and carried out the mass murder in Novi Sad were put on trial in Budapest. Not for murder, but rather for violating the code of honor of the Hungarian forces, since the operations they carried out in the Voivodina province had not been approved by their superiors. All of them, including Kepiro, were convicted and sentenced either to death or to lengthy prison terms. The convicted officers, however, never served their sentences since shortly after the end of the trial and before they could be implemented, Nazi Germany occupied Hungary and pressured the Hungarians to cancel the convictions and the punishments. Thus Kepiro's identity and participation are not in doubt, having already been duly confirmed by a Hungarian court. In fact, Kepiro himself admits his participation in the Novi Sad operation, but simply denies having committed any "war crimes." In that context, a fascinating aspect of Kepiro's behavior in Novi Sad came to light during his 1944 trial. When Kepiro was briefed on his assignment before the roundups and murder took place, he asked for the orders in writing. Already a lawyer, he apparently immediately recognized their immorality and consequent illegality. His superior responded, however, that orders of this kind were only transmitted verbally, and Kepiro carried them out loyally. Ironically, this behavior prompted the Hungarian court to reduce his jail sentence, but in theory they should have done the opposite, since Kepiro was, in essence, the worst type of Holocaust perpetrator, an intelligent and educated professional who clearly understood that what he had been told to do was totally reprehensible, yet did it anyway. He was obviously a person who was more concerned about his alibi than about the fate of his innocent victims, and thus someone undeserving of any sympathy. ON AUGUST 1, it will be three years since I initially notified the Hungarian authorities that Kepiro was alive and living in Budapest. (After the war, he had escaped to Austria and from there to Argentina, where he lived for 48 years.) At that time, the prosecutors assured me that if he had committed war crimes (which obviously was the case), they would immediately implement his original sentence, but six months later I was informed that this was not possible since a Hungarian court had cancelled his conviction. Instead, prosecutors launched a new investigation against Kepiro, which in theory should have long ago resulted in a trial. But the wheels of justice for a Hungarian Nazi war criminal turn incredibly slowly and without external pressure it appears very doubtful whether Kepiro will ever be punished for his crimes. In the meantime, he is conducting an active legal battle against his prosecution and giving numerous interviews in which he protests his innocence, while admitting his presence in Novi Sad on January 23, 1942. In these days in which the nationalist extremist Magyar Garda march in the streets of Hungary in black uniforms with symbols reminiscent of the wartime fascist Arrow Cross, and the racist and anti-Semitic Jobbik party garnered 15 percent of the votes in the recent elections for the European Parliament, the fate of an elderly Hungarian Nazi war criminal may not seem particularly pressing. The fact is, however, that precisely by mustering sufficient political will to bring to justice people like Kepiro, the government will be sending an unequivocal and necessary message to Hungarian society and especially to the ultranationalists that the days of Arrow cross terror, anti-Semitism and racism are long gone never to return and that democratic Hungary will not countenance their revival. Now if only Prime Minister Banjai's hosts in Jerusalem will make sure to deliver the message loud and clear. The writer is director of the Israel office of the Simon Wiesenthal Center.