There is increasing concern worldwide about Iran’s nuclear weapons program, in view of the failure of the recent Moscow talks between Iran and major powers (the UN’s Permanent Security Council members and Germany).

Though American intelligence has recently assessed that Iran’s leadership has yet to decide whether actually to build its first nuclear weapon, there is little doubt that Iran seeks the technical capability to assemble such arms rapidly, should it make the decision to “go nuclear.” For all intents and purposes, such a technical capability is tantamount to having nuclear weapons. It has been argued that Iran, surrounded by hostile forces (above all American), needs nuclear weapons in order to deter other countries from attacking it. Interestingly, those who contend that the United States intends to attack Iran to gain control of its oil cannot answer the question: “What is the U.S. waiting for?” The U.S. has long had the capacity to mount a highly destructive attack on Iran. While many outside Iran (and indeed inside) would like to see the end of the current regime of ayatollahs, there is no evidence that any country intends to attack Iran for any reason at all, with one possible exception — to end its nuclear weapons program.

Iran’s nuclear weapons program may indeed be — at this time — for defensive purposes only, emphasis being on the phrase “at this time.” It has also been argued that it is only “fair” that Iran should be allowed to have nuclear weapons, since countries such as Israel possess them. This argument may appeal to some, but it has no traction in the real world of international politics. The stakes involved are simply too high to allow any argument of the “justice” of Iran having nuclear weapons to trump the vital national security interests of countries to which Iran is hostile.

The most chilling scenario is often overlooked: other countries in the region, should Iran make nuclear weapons, will also seek to get them. The prospect of a number of countries in the Middle East having fingers on the nuclear trigger markedly increases the possibility of a nuclear war, started either by design, or more likely by miscalculation, borne of fear of the intentions of hostile neighbours.

Israel is of course the country most concerned about the Iranian nuclear weapons program. Irrespective of the exact words used by Iranian leaders when talking about Israel, the tone is unquestionably menacing. Indeed, it is more than just words. Iran continues to arm both Hezbollah terrorists in Lebanon and Palestinian terrorists in the Gaza Strip with increasingly long-range rockets and missiles, some of which have already been launched against Israel. The first shots in the war underway between Israel and Iran were fired long ago by Lebanese and Palestinian militants. This is not a cold war.

It is however highly unlikely that the current Iranian regime would actually strike Israel with a nuclear weapon, since the Israeli nuclear response would be devastating to Iran. There is no evidence that Iranian leaders are suicidal. Survival of Iranian regime and of the Iranian Islamic revolution are their top priorities, not nuclear war with Israel.

However, what is poorly appreciated is that, while it may well be highly unlikely that the present Iranian leadership would fire a nuclear weapon at Israel, highly unlikely is not the same as one hundred per cent guaranteed. This is the deep Israeli fear. And the possibility that an irrational Iranian military commander who has the ability to launch a nuclear-armed missile might decide to do so, contrary to the intent of Iran’s political leaders, cannot be dismissed. Equally relevant, no one can be certain that future Iranian political leaders will not themselves be irrational, and willing to attack Israel regardless of the undoubted Israeli response. Finally, it is not just Israel that is a possible target. So too are countries in Europe, as Iran develops missiles of ever greater range. In this context, should the West elect to take such risks and abandon efforts, if necessary the last-resort military option, to prevent Iran from acquiring nuclear arms?

Given its very small size, Israel has only to be wrong once about Iran to suffer the devastating consequences of an Iranian nuclear attack.

One Iranian nuclear weapon striking Tel Aviv would rip the economic heart out of the country and inflict massive psychological damage on the survivors. Even the small American atomic weapons used against Hiroshima and Nagasaki (13 kilotons and 21 kilotons respectively) in 1945 killed some 70,000 Japanese in each city. Thousands more died from the effects of radiation later. A similarly small Iranian nuclear weapon, within Iran’s capacity to produce, would kill tens of thousands in Tel Aviv.

Many surviving Israelis would elect to leave the country permanently, unwilling to risk themselves and their families to the possibility of a second attack. The continued existence of Israel would be in severe doubt. The Israeli nuclear counterattack against Iran would leave Iran utterly devastated, though this would be at best cold comfort to surviving Israelis.

Increasingly, there are calls for Israel and the United States to take military action to halt Iran’s nuclear program. Whatever the exact outcome of an attack on Iran, the costs will be high to the world. But there is no question, given Iran’s relatively weak military, that Iranians would be the biggest losers.

It is therefore in Iran’s best interests to give up its nuclear adventure. As much as Israel and the rest of the world would benefit, the Iranian people themselves would be far more secure as a result of such a responsible decision.

Retired Canadian Forces Colonel R. Geoffrey St. John was the Canadian Defence Attaché to Israel from 2004 to 2008.