We've seen it before. The same thing happens when respectable institutions try to wage a campaign against something deplorable - for example, when attempts are made to ban a pornographic film or try an Arab poet because of a poem inciting against Israel. The official reaction often ends up providing the porno film or inflammatory poem, which might otherwise have been virtually ignored, with a free public relations campaign. That is why it is often very tempting to refrain from declaring war on an undesirable phenomenon. But there are some things that we must not ignore - because our silence could be interpreted as an admission of guilt. The conference of Holocaust deniers held in Teheran under the sponsorship of Iranian President Ahmadinejad was a provocation that compels us to respond to very strongly, even if that response gives the conference an additional dimension. Those conversant with the subject are familiar with the names of the participants in the conference. Neither historians nor scholars, they are a bunch of garbage-pail anti-Semites who make a living from denying the Holocaust. If the conference were an isolated incident, we could perhaps dismiss it with contempt, as part of a bizarre phenomenon. But the moment it becomes a link in a chain of activities aimed at preparing the ground for Israel's destruction, we have no choice but to relate to the conference with all due gravity. Moreover, supporting the conference is not a lunatic-fringe neo-Nazi organization, but rather the fanatical government of a major and wealthy Middle Eastern Muslim country. AND THIS is the chain: Iran provides the money, arms and instructors to Hizbullah in Lebanon. Iran supports Hamas in the territories. Iran manufactures long-range ballistic missiles capable of reaching any target in Israel. Iran is investing enormous resources to manufacture a nuclear device and is willing to take on the entire world to do so. The Iranian government is intensively involved in denying the Holocaust based on the assumption that the memory of the destruction of European Jewry gives Israel an umbrella - Europe's guilty conscience. "If the occurrence of this event [the Holocaust] is cast in doubt," said the Iranian Foreign Minister Manouchehr Mottaki, "the identity of the Zionist regime will also be cast in doubt." And last but not least: The president of Iran has publicly declared that Israel should be wiped off the map. All this together proves that what is involved here is not a spontaneous eruption of hatred, but rather a systematic and dynamic campaign, whose components are all aimed at a single goal. Suddenly, we find ourselves in a new situation that is difficult for us to take in. Since the Second World War, no serious organization, not to mention a state, has denied the Holocaust. The attempt made a few years ago to hold a conference of Holocaust deniers in Beirut was obstructed - interestingly enough - by Arab intellectuals. Despite the many conflicts throughout the world - between countries, nations and religions - no leader of any sovereign state has called for the destruction of another one. The call by the Iranian president to wipe Israel off the map of the Middle East is unparalleled anywhere else in world politics. One would have to be blind not to see the writing on the wall. As recently as a year or two ago, no one could have imagined that the president of any state in the world denying the Holocaust and calling for the destruction of Israel. Now, we find ourselves in the absurd situation of having to prove that the Holocaust is not a hoax and that the State of Israel has the right to exist. Not only the nations of the world, but Jews too once dismissed Hitler as a madman whom no one need take seriously. It would be a tragic mistake to give in to that illusion once again. The author is the chairman of the Yad Vashem Council.