The cliché about the annual Herzliya conference is that anyone who is anyone in discussions about Israel’s security is there. But that’s not quite true. Rather, everyone is there — from the most senior Israeli politicians, soldiers and advisers to students, foreign experts and even grubby hacks.

Most years there tends to be a theme on everyone’s lips. This year, there were two.

It would have been odd if the Iranian nuclear bomb wasn’t one of them, since it is the first existential threat Israel has faced for decades — and is also forcing Arab countries to confront the danger of a dominant Iran.

Indeed, George Mitchell, the American special envoy, tells colleagues that on his negotiating trips around the Arab countries, only 10 per cent of his meetings are spent on the Palestinians and 90 per cent on Iran.

The clear message is that sanctions are now going to happen. But getting Security Council agreement for worthwhile sanctions is far from certain, although Israeli diplomats have a working assumption that if Russia can be brought on board — and they think it can — China will follow.

But there is a Plan B. Even if the UN fails to deliver, so-called “like-minded countries” — such as Canada, Australia, South Korea, Japan, the US and, yes, the EU (which seems to have grasped the need for action) — are free to impose their own, harsher sanctions. In some ways this could even be preferable.

Iran is not the only existential threat. The other dominant topic is the delegitimisation of Israel.

Rather than merely criticising Israeli policy, there is now an undercurrent in some places that it is Israel itself which is the problem, a theme which has been adopted by some left-liberals who argue that in the modern world, a state based on ethnicity is illegitimate.

This is not just words; it has a real impact. Take the stalled negotiations with the Palestinians (which remain on hold although Mr Netanyahu did say in Herzliya that he hopes for talks to be renewed “in coming weeks”).

In theory, the stumbling block is the Palestinian Authority’s demand that the Israelis freeze building in “occupied” east Jerusalem as a pre-condition for talks. PM Netanyahu’s announcement last year of a 10-month settlement freeze is not enough for them, and the world asks why Israel cannot just show good faith and accede to the Jerusalem demand.

But there’s something else going on here. For 16 years after Oslo, the Palestinians were prepared to negotiate while settlements were being built.

Now there is a freeze, they won’t talk. As Israel softens its position, the Palestinians harden theirs and make a demand on east Jerusalem to which not even the most peacenik politician would accede in advance of talks.

This is not a stumbling block; it is the whole point. As a senior Israeli official put it to me, the Palestinians do not want negotiations, they want to get the pressure off them to return to talks without returning to talks, so they have demanded as a pre-condition something they know cannot be met by Israel.

Why don’t they want to negotiate? Because rather than bilateral or even multi-lateral talks involving a grand bargain with Syria and the Arab states brokered by the US, the Palestinians want to proceed through forums such as the UN and EU, where they have knee-jerk support, and where the very question of Israel’s legitimacy as a nation is being raised.

Everything connects.