Beyond the rhetoric’s relating to the Iranian menace lies a clear and present danger to the very existence of Israel.

The rhetoric is that Iran, by defying the international community, threatens world peace and that its insistence on manufacturing nuclear bombs as well as long-distance missiles destabilizes the Middle East. The facts are that only one country is the immediate target for a nuclear holocaust: Israel: The rhetoric is that international pressure and the threat of sanctions may deter Iran from proceeding in its destructive plans.

The fact is that there is no indication, that such pressure and possible threats of sanctions – which in all probabilities will anyway be vetoed by China and Russia – will be efficacious. The facts are that the president of a powerful and rich country openly threatens to wipe Israel off the map; that Israel is tiny and totally vulnerable to such attacks; that in fact one well-aimed Hiroshima-type old fashioned nuclear device could destroy the Jewish state and thus complete that which President Ahmadinejad claims did not happen in Europe. That this danger, for some mysterious reason, is ignored by professors John Mearsheimer and Stephen Walt in their bash-Israel-and-the-Jews “Israel Lobby” paper does not derogate from these dangers.

Can mutual deterrence of the sort that saved humanity during the Cold War be effective here? Such an assumption is doubtful. The motives that move Iran’s leadership are fundamentally religious, and rational considerations play little, if any, role. Consider the fact that Iran’s president is not deterred by the fact that “wiping off” Israel would inevitably mean “wiping off” tens of thousands of devout Palestinian Muslims – for whom this jihad is ostensibly launched. Furthermore, Iran’s president must take into consideration the possibility of some sort of Israeli reprisal on Iran especially after Shimon Peres’s blunt warning to this effect, but that knowledge does not seem to cool his fervor. Indeed, Iran’s policy on nuclear armament and its threats to annihilate Israel elevates the ideas of suicide bombers to the level of national strategy.

In the absence of deterrence and lack of effective sanctions, what can Israel do? Very little. It cannot, and should not, go it alone and launch a preemptive strike on Iran’s well-defended underground nuclear-arms industry.

Only a clear message to Iran can be effective. Such a clear message would be to include Israel in a defense pact with the U.S., and preferably within NATO, possibly together with a non-Islamist Arab state such as Jordan or Lebanon. This would be a clear warning to Iran to refrain from any attempt at “wiping off” Israel. If this clear warning is not heeded, then the time will come for a preventive strike, not by Israel alone but by a coalition of nations that realize the dangers to humanity emanating from a genocidal, nuclear-armed Iran.

All this may seem unnecessarily alarmist. But the history of the 20th century has taught us to take seriously threats uttered by armed dictators full of hate and ill will.

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