Iran’s latest defiance of the International Atomic Energy Agency says it all: Further diplomacy has no chance of stopping Iran’s nuclear programme. Neither will UN sanctions have any effect. Unless there is a timely defensive first strike at pertinent elements of Iran’s expanding nuclear infrastructures, it will acquire nuclear weapons. The consequences would be intolerable and unprecedented.

A nuclear Iran would not resemble any other nuclear power. There could be no stable “balance of terror” involving Iran. Unlike nuclear threats of the cold war, which were governed by mutual assumptions of rationality and mutual assured destruction, a world with a nuclear-armed Iran could explode at any moment. Although it might still seem reasonable to suggest a postponement of pre-emption, the collateral costs of any such delay could be unendurable.

Ideally, a diplomatic settlement with Iran could be taken seriously. But in the real world, we must compare the price of prompt pre-emptive action against Iran with the costs of both inaction and delayed military action. Iranian president Mahmoud Ahmadinejad maintains that his country’s nuclear programme is intended only to produce electricity, but there is no plausible argument or evidence to support this claim. Meanwhile, Ahmadinejad’s genocidal intentions toward Israel are abundantly clear.

Iran must be stopped immediately from acquiring atomic arms, and this can only be accomplished through “anticipatory self-defence.” Precise defensive attacks against Iran’s nuclear assets would be effective — and they would be entirely legal. It would be lawful because the US and/or Israel would be acting in self-defence. Both countries could act on behalf of the international community and could do so lawfully without wider approval. The right of self-defence by forestalling an attack has a long and authoritative history in international law. In the 1625 classic On the Law of War and Peace, Hugo Grotius expresses the enduring principle: “It be lawful to kill him who is preparing to kill….”

We must act very quickly on Iran. Many critics will argue that the expected consequences of any prompt pre-emptive strike would be overwhelming, including greatly expanded terror attacks against assorted Western targets, and perhaps regional or even global war. Although such dire prospects should not be dismissed, there is certainly no reason to believe that an American or Israeli pre-emption would make them more likely.

A more important reservation about pre-emption involves tactical difficulties. Due to delays, the success of strikes against certain key Iranian targets may already be in doubt. Worse, such strikes would probably entail high civilian casualties because Iran has deliberately placed sensitive military assets amid civilian populations - an international crime called “perfidy.” But further delay will only multiply the number of casualties from any future operation, or — in the worst-case scenario — allow Iran to beco-me fully nuclear. — The Christian Science Monitor