The way a war is waged, and to some extent its outcome, may depend on how adversaries imagine it before it starts.

As tension rises between the Islamic Republic and potential adversaries, led by the United States, how do both sides imagine a war that we must hope would not happen?

In Tehran, the virtual exclusion of President Mahmoud Ahmadinejad from decision-making means that, for the first time since 1989, the Islamic Republic is under a single command symbolized by “Supreme Guide” Ali Khamenei.

Khamenei, who now likes to call himself “Imam”, may well be a puppet of the military-security apparatus. But what matters for this discussion is that the time when different voices could be heard within the establishment has ended. The presidency has been reduced to an embarrassment and the Majlis, the supposed legislature, has turned into a club of adulation for “the Imam.” Khamenei and his entourage believe that war with US is inevitable.

But how do they imagine that war?

In a speech last month, Khamenei hinted that Tehran was preparing to abandon its 32-year old low intensity war against the US in favour of a high-intensity strategy.

“We are not the type to sit back and watch as powers made of straw, and rotten to the heart, threaten our steadfast and steel-like nation,” he said. “Faced with aggression, we know how to be offensive.”

Four days later, the Deputy Commander of the Islamic Revolutionary Guard Corps (IRGC) General Muhammad Baqeri told the Majlis that Khamenei’s speech indicated “a change in Iran’s Defense Doctrine.”

Baqeri indicated that Tehran’s strategists believe that the US would carry out a series of air strikes against the Islamic Republic before launching a ground offensive. And, when the war starts on land, Iran’s huge size and difficult terrain would defeat “the invaders”.

“The outcome of the war will be decided on land,” the general said. “And the land of Iran belongs to the Iranian people.”

Piecing together the two speeches, it seems that Tehran imagines the war like this: The Americans will bomb Iran’s suspected nuclear sites while assembling forces for a land invasion. Iran will retaliate by attacking US forces in the region while ordering the Lebanese branch of Hezbollah and the Palestinian Islamic Jihad to fire rockets against Israel. The conflict will last a couple of weeks after which mounting US and Israeli casualties, accompanied by worldwide anti-war demonstrations, would force Washington to stop its “aggression”. The “Imamate” would emerge wounded but alive, its nuclear project and prestige intact.

What if the war doesn’t happen as Khamenei imagines?

To start with, air strikes may be more than the pinpricks Tehran imagines. Since the Iraq war, the US has increased its fire-power fourfold. It has manufactured “bunker-busting” bombs capable of destroying even the deepest mountain hideouts in places like Fardo. The “bunker-busters” are the world’s most powerful weapons, short of nuclear warheads. According to the Centre for Strategic Studies, almost 400 of these are now “in position”, aimed at Iran.

Next, it is not certain that air strikes would be limited to nuclear sites. Wouldn’t US strategist think of first wiping out Iran’s air, missile and naval assets that could be used to defend the nuclear sites? And wouldn’t the attempt to destroy such targets require the dismantling of Iran’s command-and-control systems?

According to Dan Plesch of the London University, the US is “gearing up totally for the destruction of Iran”.

The US plan is to destroy over 10,000 targets in Iran within a few hours. Because suspected nuclear sites do not number more than a dozen, it is obvious that Iran’s conventional military assets and economic and industrial centres would represent the overwhelming majority of targets.

Retaliating against US forces “in the region” won’t be relevant to the conflict. By the end of the year there would be few US troops in Iraq for Jaish al-Mahdi and other Iran-financed groups to harass. Attacking US forces in Afghanistan would be declaring war on NATO.

In any case, the air strikes would be carried out by the US Air Force operating from the Indian Ocean island of Diego Garcia, beyond any retaliation Tehran might imagine.

With Iran’s nuclear, military and economic assets destroyed, the US would have little interest in invading a failed state.

Khamenei’s threat of closing the Strait of Hormuz is also dubious. Shutting the chokepoint would need months to impact global oil supplies. Furthermore, the inauguration of the Fujairah pipeline would reduce the effect of any closure of Hormuz. Closing Hormuz would also shut Iran itself out of the oil market.

What about how the US imagines war with Iran?

Under Barack Obama the US has returned to the doctrine of long distance war discarded by George W Bush with the invasion of Afghanistan and Iraq.

Now, Washington imagines a short war from the air that would enable opponents within the Khomeinist establishment to topple Khamenei, repeating what happened to Slobodan Milosevic in Serbia.

But what if the Khomeinist regime, wounded but alive, accepts to halt the nuclear project to gain time to suppress internal opponents? And what if a year or five years later, the same regime resumes its nuclear project?

In any shape or form, the Khomeinist regime would remain a thorn in the side of the United States and its allies. Khamenei is running a regime that cannot be reformed. What it does is dictated by its political DNA.

The question that Obama must ask before triggering a war is whether military action would alter that DNA?