There is one advantage to President Ahmadinejad’s latest outburst at the University of Tehran: It removes the fog of misinformation and misunderstanding surrounding the major issue of the Middle East — the survival of the Jewish state. That issue, or rather the Arab and Muslim opposition to Israel’s existence, has not really disappeared since 1948, when the Arabs sought to annihilate the fledgling state.

Nevertheless, in recent years there were encouraging signs that the Arab world, having failed to crush Israel militarily, would learn to co-exist with the “Zionist entity” once Israel would relinquish the territories occupied in the 1967 war. At the same time, Israel bashers have waged a campaign against Israel describing the Jewish state as an invincible superpower guilty of the most heinous crimes against humanity. Recently, two prominent American professors, Stephen Walt and John Mearsheimer, in their paper, “The Israel Lobby and U.S. Foreign Policy,” described the Jewish state as immune from all danger and discounted the notion that Iran poses any threat to Israel.

Now the situation has changed. A non-Arab regional power — Iran — is threatening Israel. This past summer’s war in Lebanon, which actually was the first skirmish with a well-equipped, Iranian-supplied army called Hezbollah, proved Israel’s extreme vulnerability. Throughout the Muslim world, the encounter was viewed as the first defeat suffered by the “infidels.” Iran, armed with this alleged victory, is lashing out with even more vitriol against the “heathen state” of Israel. Iran’s president, emboldened by his reception in the United Nations and at the Council on Foreign Relations, bluntly repeats his threats: to annihilate Israel and punish the West for supporting its existence. He compounds this by denying not only the Holocaust but also the Bible, saying that there have never been Jews in the holy land.

Shimon Peres rightly reacted to this diatribe by calling Iran’s president the new Hitler and by chiding the Council on Foreign Relations for inviting him to speak to that august body (where, by the way, he claimed that “Iran was freer then the U.S.”). Like Hitler, Mr. Ahmadinejad intends to carry out his threats. Unlike Hitler, who concealed his plans for the Final Solution, defining them as top “Reich’s secret,” and even resorted to camouflaging his deeds, Iran’s president blares out his plans for a new Final Solution.

Mr. Ahmadinejad does not joke. He has the means to carry out his threat: Iran already has substantial missile capabilities and will soon have, unless forcibly stopped, nuclear arms. Israel is not only tiny — a speck on the map of the Middle East — but it is totally unprepared for such a destructive blow. It has no shelters suitable to withstand a nuclear bombardment, it has no alternative sites to which people can retreat while awaiting cleanup of contaminated areas, and it has no operative anti-missile defense system. Retaliation and the balance of terror that saved the world from nuclear Armageddon during the Cold War may not be sufficient to deter a fanatical regime that regards “wiping Israel off the map” as a divine duty necessary for ushering in a new, blissful Islamic era.

What should be done to prevent Iran’s destruction of Israel? Even if Israel could technically deliver a devastating blow to Iran’s underground genocide industry — a doubtful proposition, at best — it lacks the international clout to do so. It must rely on a defense pact with America — either within or outside NATO — to possibly deter the Iranian leadership from implementing its terrible threats. At home, Israel should prepare itself for doomsday with a passive defense system, including nuclear shelters.

Above all, Israel must lead the world in developing an advanced, fail-proof anti-missile system, which is essential for the protection not only of Israel but of the whole civilized world, for the threat from Iran is not merely a new facet of the conflict in the Middle East. Iran and North Korea are harbingers of a new era of nuclear proliferation, in which dictatorial regimes have a clear advantage over democracies. Only an effective anti-missile defense system — technically feasible, economically exorbitant — can lessen this danger. Actually, such a system is more essential now than in the star-war days of the Cold War. The Soviet Union was a calculating, rational empire. This new era will place missiles and weapons of mass destruction in the hands of madmen, who seek to destroy civilization as we know it.

Israel requires assistance in this endeavor. Israel has the know-how, but lacks the means to develop such a system. A joint program with America is the appropriate response to the new genocidal threats emanating from both the Middle and the Far East.

Mr. Rubinstein is president of the Interdisciplinary Center Herzliya in Israel.