In his televised Sept. 11 address, President Bush said that we must not "leave our children to face a Middle East overrun by terrorist states and radical dictators armed with nuclear weapons." There's only one such current candidate: Iran.

The next day, he responded thus (as reported by Rich Lowry and Kate O'Beirne of National Review) to a question on Iran: "It's very important for the American people to see the president try to solve problems diplomatically before resorting to military force."

"Before" implies that the one follows the other. The signal is unmistakable. An aerial attack on Iran's nuclear facilities lies just beyond the horizon of diplomacy. With the crisis advancing and the moment of truth approaching, it is important to begin looking now with unflinching honesty at the military option.

The costs will be terrible:


· Economic . An attack on Iran is likely to send oil prices overnight to $100 or even to $150 a barrel. That will cause a worldwide recession perhaps as deep as the one triggered by the Iranian revolution of 1979.

Iran might suspend its own 2.5 million barrels a day of oil exports and might even be joined by Venezuela's Hugo Chavez, asserting primacy as the world's leading anti-imperialist. But even more effectively, Iran will shock the oil markets by closing the Strait of Hormuz, through which 40 percent of the world's exports flow every day.

Iran could do this by attacking ships in the Strait, scuttling its own ships, laying mines or just threatening to launch Silkworm anti-ship missiles at any passing tanker.

The U.S. Navy will be forced to break the blockade. We will succeed, but at considerable cost. And it will take time -- during which the world economy will be in a deep spiral.


· Military . Iran will activate its proxies in Iraq, most notably, Moqtada al-Sadr's Mahdi Army. Sadr is already wreaking havoc with sectarian attacks on Sunni civilians. Iran could order the Mahdi Army and its other agents within the police and armed forces to take up arms against the institutions of the central government itself, threatening the very anchor of the new Iraq. Many Mahdi will die, but they live to die. Many Iraqis and coalition soldiers are likely to die as well.

Among the lesser military dangers, Iran might activate terrorist cells around the world, although without nuclear capability that threat is hardly strategic. It will also be very difficult to unleash its proxy Hezbollah, now chastened by the destruction it brought upon Lebanon in the latest round with Israel and deterred by the presence of Europeans in the south Lebanon buffer zone.


· Diplomatic. There will be massive criticism of America from around the world. Much of it is to be discounted. The Muslim street will come out again for a few days, having replenished its supply of flammable American flags, most recently exhausted during the cartoon riots. Their governments will express solidarity with a fellow Muslim state, but this will be entirely hypocritical. The Arabs are terrified about the rise of a nuclear Iran and would privately rejoice in its defanging.

The Europeans will be less hypocritical because their visceral anti-Americanism trumps rational calculation. We will have done them an enormous favor by sparing them the threat of Iranian nukes, but they will vilify us nonetheless.

These are the costs. There is no denying them. However, equally undeniable is the cost of doing nothing.

In the region, Persian Iran will immediately become the hegemonic power in the Arab Middle East. Today it is deterred from overt aggression against its neighbors by the threat of conventional retaliation. Against a nuclear Iran, such deterrence becomes far less credible. As its weak, nonnuclear Persian Gulf neighbors accommodate to it, jihadist Iran will gain control of the most strategic region on the globe.

Then there is the larger danger of permitting nuclear weapons to be acquired by religious fanatics seized with an eschatological belief in the imminent apocalypse and in their own divine duty to hasten the End of Days. The mullahs are infinitely more likely to use these weapons than anyone in the history of the nuclear age. Every city in the civilized world will live under the specter of instant annihilation delivered either by missile or by terrorist. This from a country that has an official Death to America Day and has declared since Ayatollah Khomeini's ascension that Israel must be wiped off the map.

Against millenarian fanaticism glorying in a cult of death, deterrence is a mere wish. Is the West prepared to wager its cities with their millions of inhabitants on that feeble gamble?

These are the questions. These are the calculations. The decision is no more than a year away.