The third round of talks between Iran and the "P5+1" group, held in Moscow on 18-19 June 2012, ended in stalemate. A formal process will continue at a lower level, but amid an atmosphere of continuing mutual suspicion and in a situation where United States electoral politics work against compromise. Iran believes that most of the P5+1 is bargaining that sanctions increase their impact until Tehran bends to its will, whereas Washington holds that it is the Iranians who are happy to prolong matters while they accelerate uranium enrichment (see "Syria and Iran: a diplomatic tunnel", 25 June 2012)..

Alongside these calculations, at least some European (especially German) politicians recognise that any substantial delay in negotiations could well create the space for a unilateral Israeli military strike on Iran, an act that would inaugurate a lengthy period of deep instability and perhaps an intensely destructive war.

The high European commitment to diplomacy over Iran has in part been motivated by the risk of Israel attacking Iran. There is little doubt that Israel would be prepared to make such a move at a time of its choosing. It is of even greater concern to the Europeans, then, that indications have emerged in recent weeks of the Pentagon's own serious engagement in comprehensive multi-option war-planning.

A question of timing

The belief underpinning this hawkish approach seems to be that a short, sharp military action directed very precisely at Iran's nuclear and missile facilities is the only way to force a weakened Iran to "come in from the cold" and - once and for all - abandon its nuclear ambitions.

There is no settled consensus in elite US circles about to handle the Iran problem. Several powerful voices, including within the Pentagon, argue that the best option is to continue the mix of sanctions and sustained cyber-warfare (the latter in collaboration with Israel). Others, however, argue that there is a need to plan for war, with the question of optimum timing a central issue (see David Fulghum, "Bombing Iran: U.S. military planners ponder when a kinetic attack might make sense", Aviation Week, 25 June 2012).

The Pentagon advocates of a strike on Iran believe that the early part of 2013 might be the best moment. In their eyes, this offers three advantages. First, the presidential and congressional elections of November 2012 would be out of the way, with nearly two years to the next mid-sessional elections; thus any political controversy would have plenty of time to diminish. Second, the months between now and the point of decision would make clear whether there was any possibility of a political compromise. Third, keeping the war option open - and informing the Israelis well in advance - would make a lone Israeli attack less likely. The most hardline of the US planners hold the view that it is much better that the US "does the job properly" than lets Israel, with its much smaller forces, take the lead.

The planners emphasise here the sheer power of the United States military, especially the ability of the US air force (Usaf) to fly from bases in the region and combine with naval-aviation forces operating out of carrier-battle groups in the Arabian Sea.

The key weapons used would be the B-2 strategic stealth bombers and the F-22 strike-aircraft, which would overfly Iran after the latter's defensive radar installations had been jammed by the new miniature air-launched decoy (Mald) and other systems.

The B-2 strategic stealth bomber would be a key component, given its ability either to drop more than forty bombs in a single sortie or to deliver very large earth-penetrating bombs. But its dependence on extensive base-support facilities means that the B-2 can operate only from a handful or air-bases worldwide; the most relevant candidates are RAF Fairford in Gloucestershire, western England, and Diego Garcia, a British-controlled atoll in the Indian Ocean. Britain would thus be directly involved in the war from the start.

In addition to the B-2s and F-22s, other planes - F-15E and F-16 strike aircraft - would be deployed to launch joint air-to-surface stand-off missiles (JASSMS) from outside Iranian airspace. A key system here is the AGM-158 Jassm-ER, a new version of which has a range of 575 miles (more than double the current 230-mile version) and is being deployed in 2013.

The Usaf planes would be central to the assault on Iran, but the US navy would also attack with sea-launched cruise-missiles (launched from cruisers, destroyers and submarines) and stand-off air-launched missiles (launched from F/A-18s flying from the carriers).

A state of mind

All these systems (and there are many others) amount to far more than Israel can deploy. But the distinctive aspect of the plan is less its scale or the perceived need to take charge from Israel than the idea that underpins it, at least among some of the planners: namely, that a focused, single-minded attack aimed specifically at Iran's nuclear and missile facilities will intimidate Iran into an acceptance that its nuclear ambition is a lost cause.

The respected defence journal Aviation Week quotes one strategic veteran: "We should give Iran advanced warning that we will damage and likely destroy its nuclear facilities. It is not an act of war against Iran, the Iranian people or Islam. It is a pre-emptive attack solely against their nuclear facilities and the military targets protecting them. We will take extraordinary measures against collateral damage."

It should be emphasised that an American attack is neither imminent nor even likely (at least for now). But if negotiations with Iran fail, if Mitt Romney wins the presidential election and the Republicans control at least one house of Congress, then things could begin to look very different in the early months of 2013.

Perhaps the most significant element of this scenario is that if it came to a war, the Iranians would readily give up in the face of such great force. The assumption is extraordinary, yet the underlying mentality is familiar: it also produced the belief that the Taliban was finished by the end of 2001 and the Iraq war was over in three weeks flat in March-April 2003. It seems that nothing has been learned from the experience of two long and bloody wars, and that is the real cause for worry.