Despite this climate, Tehran thinks it can play its old tricks. It is seeking to thwart the International Atomic Energy Agency's right to inspect sites where it is enriching fissile material or developing technologies ancillary to a weaponised bomb. The IAEA has evidence that the Iranians have been removing soil from Parchin where they have been making nuclear triggers, while the agency has been denied access to the underground enrichment facility at Fordow. The big imponderable is whether Iran will stick at "threshold status" or go for "breakout".

The Iranians have sought to spin out the group of five plus one talks chaired by Baroness Ashton, so that in Baghdad all they agreed was to meet again in Moscow with the agenda, naturally, subject to further Iranian filibustering. The worst thing Western negotiators could allow is some sort of "goodwill" relaxation of sanctions to coax Iran into negotiations they have no intention of honouring.

But Europe is a marginal player. The US and Israel have different red lines for the moment when diplomacy is deemed exhausted: Israel by the end of 2012, when air strikes might still have a disabling effect, the US in 2013 because of the hiatus of the presidential election. Major-General Amos Yadlin does not think Israeli air strikes would be effective — in 1981 he was one of the F-16 pilots who took out Saddam's Osirak reactor — without massive US involvement to get the job done. A Gulf of Tonkin moment might prove highly useful in the Persian Gulf. 

Since Israeli public opinion does not want to get out of step with the US, we will have to see whether, for once, Israel sets aside its right to self-defence by relying on its most powerful ally. Hence possibly the most significant thing I heard in Tel Aviv was when Ehud Barak said he had told former US defence secretary Robert Gates: "This [US] administration has done more to safeguard Israel's security than any I can remember," words the massed generals and spooks greeted with applause. Meanwhile, fine minds are turning to how to manage the aftermath of air strikes.