An Israeli attack on Iran seems inevitable. If it succeeds, it will return to Israel its deterrent power and send a clear message to the saber-rattling jihadists that they were too early in beginning the countdown for the disappearance of the Jewish state. If it fails, or fails to achieve the majority of its objectives, it could amount to an act of national suicide. Fanatical Muslims on every side will be encouraged by the failure and outcome of an Iranian retaliation which would cause heavy damage to the whole center of our country. Iran would unquestionably be joined by its proxies on our borders, Hizbullah and Syria on the north and Hamas on the south, the PLO jihad brigades under various names, and the Arabs of Israel. The latter have already shown their ability to block major traffic arteries and demonstrated that their loyalties rest with their Arab brethren, not with the Jewish state. The repeated declarations of President Mahmoud Ahmadinejad that the aim of Iran is to wipe Israel off the world map should not be taken as the empty, fiery words of a fanatical Muslim dictator, but as a plan of action. True, Iran does not need a pretext, but an Israeli attack on any nuclear installation in Iran, or just an invasion of Iranian air space could be used as an excellent reason for mounting an all-out missile attack. The damage to Iran would be serious, but not devastating. Iran has a very high tolerance level. It proved it in the early 1980s during the war against Iraq, when Teheran and other places came under destructive attacks by Frog and Scud missiles and the Iranian army suffered heavy losses on the battlefield. Iran can live with one Israeli air raid or two; not with a nuclear attack. As it seems now, Israel does not have the military facilities to deal with the distances involved and with other technical obstacles to carry out a successful attack on Iran. A combined Israeli and American effort, however, could cause irreparable damage to the Iranian nuclear program. A non-nuclear Israeli attack on Iran would be a "surgical" operation. But an Iranian-Hizbullah-Hamas attack would be indiscriminate and aimed at the major urban centers, causing tremendous harm. IRAN HAS the motivation to destroy Israel, and if it is allowed to gain nuclear weapons it will not need an excuse to do so. That motivation is a double one: messianic Shi'ite and expansionist-imperial. Since the late ninth century, the Shi'ites have been expecting the emergence of the hidden imam-mahdi, armed with divine power and followed by thousands of martyrdom-seeking warriors. He is expected to conquer the world and establish Shi'ism as its supreme religion and system of rule. His appearance would involve terrible war and unusual bloodshed. Ahmadinejad, as mayor of Teheran, built a spectacular boulevard through which the mahdi would enter into the capital. There is no question that Ahmadinejad believes he has been chosen to be the herald of the mahdi. Shi'ite Islam differs from Sunni Islam regarding the identity of the mahdi. The Sunni mahdi is essentially an anonymous figure; the Shi'ite mahdi is a divinely inspired person with a real identity. However both Shi'ites and Sunnis share one particular detail about "the coming of the hour" and the dawning of messianic times: The Jews must all suffer a violent death, to the last one. Both Shi'ites and Sunnis quote the famous hadith attributed to the Prophet Muhammad: The last hour will not come unless the Muslims fight against the Jews, and the Muslims would kill them until the Jews hide themselves behind a stone or a tree and the stone or the tree would say: "Muslim! Servant of Allah! Here is a Jew behind me; come and kill him!" Not one Friday passes without this hadith being quoted in sermons from one side of the Islamic world to the other. Shi'ism regards the Jews as an embodiment of filth and the contaminating source of ritual impurity - which adds another religious justification to the Muslims to rid themselves of the Jews and their state. Iran threatens that it has the ability to do so with its ballistic missiles and the readily available services of local proxies who would love to join the general effort to kill the Jews. THE OTHER side of Iran's motivation to destroy Israel is the imperial one. Iran has the same virus inherent in every totalitarian power - to gain imperial dominion. Totalitarian Iran wants to recreate its empire east of the Mediterranean. The leaders of modern Iran, long before the present Islamic regime, toyed with the idea of reviving the empire of Cyrus and Darius. The present Islamic regime has the same aspirations. Nuclear power is necessary to achieve this desire. As fantastic as it sounds, the destruction of the State of Israel seems necessary for the expansion to the east Mediterranean (which might include the elimination of a few Sunni entities such as Saudi Arabia and some Gulf states). LET US try a scenario in which Israel carries out a successful attack, with or without active American help, on a few key Iranian reactors. Such an operation would not completely destroy Iran's nuclear capability, but it would badly wound its national and Islamic pride. The Iranian people, including the opposition would, at least in the initial stage, rally around the ruling mullahs. The price of oil would soar, Israel would be blamed for the destruction of the West's economy, and Europe might go so far as to impose sanctions on Israel, with or without a UN decision. Moreover, being an easy target, Israel would have to brace for the inevitable Iranian retaliation. Iran would attack with the Shihab 3 ballistic missiles that carry a warhead of up to one ton and have an accuracy of 50 meters-100m. Israel has an answer to a limited number of these missiles, of which Iran has probably a few hundred. It has no answer to all the missiles that would be launched against it from three fronts. Theoretically, Iran can deliver 1,000-1,500 tons of the most modern explosives within a few days. The long-range missiles that have been supplied to Hizbullah via Damascus, and the arsenal that has been massed by Hamas in Gaza, which includes missiles that can reach Beersheba, must also be taken into consideration. There is no question that these two organizations will move into action together with Iran, and it is not impossible that Hizbullah would attempt the invasion of Israel proper to gain a local victory by occupying a border village, killing inhabitants and kidnapping a few over to Lebanon. This gruesome situation can happen any time, and not necessarily as a result of an Israeli attack on Iran. Such an attack, however, would surely bring it about. ARE THESE facts not known to the Israeli intelligence agencies? They are, but so were Hitler's intentions known to the British and the French before World War II, and they were known to the Russians before Operation Barbarosa. None of them did anything to stop the German dictator before it was too late. At the end of the war, Europe was freed. The Germans were defeated and none of the countries of Europe was obliterated from the map. In the case of Israel, there is no recovery from a one-time devastation. There is no second chance. The writer is a professor emeritus of Islamic studies at the Hebrew University of Jerusalem.