Bolton knew his words would be leaked, so maybe it was just deliberate posturing to raise the pressure on Iran. But on Sunday, addressing the American Israel Public Affairs Committee in Washington, Bolton repeated the threat: “The longer we wait to confront the threat Iran poses, the harder and more intractable it will become to solve… We must be prepared to rely on comprehensive solutions and use all the tools at our disposal to stop the threat…” He may really mean it — and no one in the White House has told him to shut up.

With the U.S. army already mired in Iraq, the Bush administration lacks the ground strength to invade Iran, a far larger country. The National Security Strategy statement of September 2002 declared a new doctrine of “preemptive” wars in which the U.S. would launch unprovoked attacks against countries that it feared might hurt it in the future, and in January 2003 that doctrine was elaborated into the military strategy of “full spectrum global strike.”

The “full spectrum” referred specifically to the use of nuclear weapons to destroy hardened targets that ordinary weapons cannot reach. Earth-penetrating “mini-nukes” were an integral part of Conplan 8022-02, a presidential directive signed by Bush at the same time that covered attacks on countries allegedly posing an “imminent” nuclear threat in which no American ground troops would be used. Indeed, the responsibility for carrying out Conplan 8022 was given to Strategic Command (Stratcom) in Omaha, a military command that had previously dealt only with nuclear weapons.

Last May, Defense Secretary Donald Rumsfeld issued an “Interim Global Strike Alert Order” putting Stratcom on high military readiness 24 hours a day. Logic says there is no “imminent” danger of Iranian nuclear weapons: last year’s U.S. National Intelligence Estimate put the time needed for Iran to develop such weapons at ten years. But experience says that this administration can talk itself into a “preemptive” attack on a country that really does not pose any threat at all.

So what happens if they talk themselves into unleashing Conplan 8022 on Iran? Thousands of people would die, of course, and the surviving 70 million Iranians would be very cross, but how could they strike back at the United States? Iran has no nuclear weapons, no weapons of any sort that could reach America. Given the huge American technological lead, it can’t even do much damage to U.S. forces in the Persian Gulf region. But it does have two powerful weapons: its Shia faith, and oil.

Iran is currently playing a long game in Iraq, encouraging the Shia religious parties to cooperate with the American political project so that a Shia-dominated government in Baghdad will turn Iraq into a reliable ally of Iran once the Americans go home. But if Tehran encouraged the Shia militias to attack American troops in Iraq, U.S. casualties would soar. The whole American position there could become untenable in months.

Iran would probably not try to close the Strait of Hormuz, the choke-point through which most of the Persian Gulf’s oil exports pass, for U.S. forces could easily dominate or even seize the sparsely populated Iranian coast on the north side. But it would certainly halt its own oil exports, currently close to 4 million barrels a day, and in today’s tight oil market that would likely drive the oil price up to $130-$150 a barrel. Moreover, Tehran could keep the exports turned off for months, since recent oil prices, already high by historical standards, have enabled it to build up a large cash reserve. (Iran earned $45 billion from oil exports last year, twice the average in 2001-03.)

So a “preemptive” American attack on Iran would ignite a general insurrection against the American presence in Shia-dominated areas of Iraq and trigger a global economic crisis. The use of nuclear weapons would cross a firebreak that the world has maintained ever since 1945, and convince most other great powers that the United States is a rogue state that must be contained. All this to deal with a threat that is no more real or “imminent” than the one posed by Iraq in 2003.

No American policy-maker in his right mind would contemplate unleashing such a disaster for so little reason. Unfortunately, that does not guarantee that it won’t happen.