THE mood at the 11th annual Herzliya conference, where Israel's top policymakers come to debate strategy and diplomacy with invited international experts, is understandably twitchy. The events in Egypt hang over the conference like the threatening grey clouds. And yesterday those clouds unleashed a savage hailstorm, in the form of a stinging attack on the Netanyahu government by Tzipi Livni, the former foreign minister who now leads Israel's fragmented opposition. Nobody here claims that they saw the upheaval in Egypt coming, and few think that President Hosni Mubarak's regime will be replaced by one that Israel will find anything like as easy to live with.

Members of the government have taken a vow of silence not to comment, even off the record, on the unfolding situation in Egypt. But if you talk to people here privately, they suggest there are three possible scenarios. The first (intended to sound incredible) is that Israel's biggest neighbour will be transformed into a peaceable, pluralist democracy. The second is that Egypt will become something like Turkey, either with an army-dominated government as in the past or with a government a bit like the present one in Ankara that has a quite a strong Islamist flavour (either more or less intense, depending on the role within it of the Muslim Brotherhood). The third is that something similar to the Iranian revolution in 1979 is played out “with dramatic consequences”. If the third scenario were to be realised, the psychological impact on Israel will be such that any conceivable land-for-peace deal with the Palestinians will have to be accompanied by much more rigorous security arrangements on the ground. That said, the emergence of a moderately Islamist government that remained committed to peace with Israel could, after the initial shock, prove quite positive.

Perhaps inevitably, the turmoil in Egypt is only entrenching people here in their existing positions. The right is saying that it goes to show how quickly things can change in the unstable Arab world. Even if you could do a deal with the Palestinian president, Mahmoud Abbas, who anyway only speaks for half the Palestinians, how confident can you be that the peace would hold? For its part, the pro-peace camp says that the situation in Egypt means that there may be only a narrow window to get a settlement negotiated and that a new urgency is required. Realistically, few people here expect this Israeli government to do very much given Mr Netanyahu's dependence on the support of parties ideologically hostile to the whole idea of “land for peace”. 

Yet neither the possibility of an Egyptian repudiation of the 32-year-old peace treaty with Israel nor the remote prospect of progress on the Palestinian front are the biggest security concerns among those at the Herzliya. Iran's nukes are still seen as the overwhelming existential threat to Israel, but the difficulties that the Iranian nuclear programme is thought to be having, thanks to tighter sanctions and the disruptive effects of the Stuxnet computer virus, are widely believed to have pushed the timeline for acquiring a bomb out to at least a couple of years from now. And that may be affecting the strategic calculus of at least some within the Iranian leadership. 

A veteran of the Sharon and Olmert governments suggested to me that if only America was prepared to do as foreign minister Avigdor Lieberman suggested last year—and impose on Iran the kind of far-reaching sanctions that have applied to Cuba for half a century—the regime in Tehran, which is already under severe economic pressure, would not last for more than 12 months. The fact that the Castro brothers are still in power seems not to weaken the argument. Generally speaking, there's a view here that America needs to get more serious about regime change in Iran, as that may be the only thing that will lead to any alteration in the country's determination to press on with becoming a nuclear power able to bully the region. As usual, however, the details of how to do it are a bit sketchy.

Of more immediate concern even than the menace of a nuclear Iran is the growing threat from Lebanon since Hizbullah's bloodless coup last month. With up to 50,000 missiles of increasing accuracy and technological sophistication having been supplied by Syria and Iran, government sources here claim that the Shiite guerrilla force (which for most practical purposes should now be regarded as Lebanon's real army) has around four times the missile power it had when it unleashed 4,000 projectiles at Israel during the bloody five-week war in 2006. The Israeli military believes that Hizbullah has also learned lessons from the conflict in Gaza two years ago and that in any future confrontation IDF soldiers will sustain significantly more severe casualties.

Despite large investments in anti-missile defences with the help of the Americans, there are fears that Tel Aviv is still vulnerable to attack from salvoes of 200km-range Zelzal II guided missiles fired from south Lebanon and cruder devices, such as the 50km-range Fajr-5 missile, that could be launched by Hamas from Gaza in the event of hostilities. In a speech yesterday General Gabi Ashkenazi, the outgoing chief of the IDF general staff, warned that while Hizbullah and Hamas could not take territory, the battlefield had now shifted to the home front. No missile shield can be fully effective, especially when the missiles fired cost a tiny fraction of the interceptors used to stop them. Israel will still need superior intelligence and the ability to put boots on the ground to defend itself.

Israelis often feel the need to remind their critical European and American friends that they live in a pretty tough neighbourhood. Special criticism among most of the people you meet at Herzliya is reserved for Barack Obama. After the row over settlement building, which many Israelis thought was the wrong fight to pick, and what is seen here as shameless flipflopping by the administration over the fate of Mr Mubarak, the kindest description of the president you will hear in Herzliya is that he is naïve. Others are harsher, saying that he is a serial blunderer who is presiding over a rapid waning of American power and influence within the region. In particular, there is both puzzlement and anger over what is seen as the very public betrayal of Mr Mubarak, which, it is claimed, will cause every moderate Arab government to review its security relationship with America. As one source puts it: “They could have told him in private that his time was up, while sticking outwardly to a position of neutrality. But by saying they supported all the aims of the protesters and telling Mubarak he must go immediately, they took a very serious, very dangerous risk.”

Correction: An earlier version of this post got the names of its missile-defence systems in a twist. This has now been fixed.