Israel's long search for impregnable security in the region has in its own view been aided by the stability of neighbouring autocracie. Egypt under Hosni Mubarak, Jordan under King Hussein and now King Abdullah, Saudi Arabia under the House of Saud, and even Syria under Hafez and now Bashar Assad - all recognised the power of Israel and were all too aware of Israel's ultimate nuclear capability.
Israel was the regional superpower, even if that could never be acknowledged.
True, uncertainty in Lebanon (and to a degree over Gaza) remained an exception to the pattern, with Syria's support for Hizbollah a continuing irritation and Israel's failures against that movement in the conflict of 2006 a source of real concern. At the same time, the Assad regime's acceptance of the status quo over the strategically vital Golan heights was a reassurance, and overall - southern Lebanon and Gaza excepted - Israel's immediate position was secure.
In the two years since the Arab awakening, such certainty has eroded: notably with Egypt (and particularly Sinai) but now much more with Syria. There is an acute concern with the United Nations peacekeepers on the Golan heights, especially as Austria's government has warned that it might withdraw its significant contingent. Austrian units make up barely a third of the total UN force, but their commitment has been substantial and a pullout could encourage others to follow suit in a way that leads to the collapse of the operation.
The triple worry
More generally, Israel's attitude to the bitter civil war in Syria is rooted in three calculations: backing to any regime in Damascus that maintains stability, enduring antagonism to Bashar Assad's support for Hizbollah, and the need to keep the Golan heights within Israel's control.
Until recently Israel felt able to restrict Hizbollah, not least by air-strikes aimed at destroying munitions destined for Lebanon, and its anxiety over the Golan heights was limited. Two outcomes of the war were considered possible - either Syria's collapse and ensuing fragmentation and inherent weakness, or the regime's survival but in conditions where it was sapped of most of its strength.
Now, though, three awkward developments are causing considerable concern in Jerusalem. The first is that the Assad regime is proving surprisingly robust and is currently on the offensive. It has, in particular, a distinct chance of breaking some of the key supply-lines for the less Islamist rebels, with the possibility of weakening them to a point close to defeat (see David Hartwell, “Battle for Al-Qusayr highlights shift in Syrian conflict”, Jane's Defence Weekly, 29 May 2013).
From Israel's perspective that would leave the more radical Islamist elements in control of much of Syria's north-east, including hydroelectric plants and oilfields. These elements would then pose an uncomfortable future threat to the Assad regime and even the possibility of Islamist pre-eminence. In turn that would in the short term strengthen the axis between Damascus and Hizbollah (whose units are now proving vital to current attempts to secure the city of Al-Qusayr).
Israel's second worry is the success of the British foreign secretary William Hague in persuading the European Union not to extend its arms embargo to Syria's rebels. This means that the Assad regime will work as hard as it can to secure more territory before the “good” rebels get boosted by European arms later in 2013.
Israel's third concern is Russia's offer to complete its agreed export contract with Damascus of S-300 anti-aircraft missiles. The version likely to be sent to Syria is the extended range S-300PMU2 system with improved multiple target-tracking capability. This is not impossible to counter, but it will complicate Israeli efforts to maintain air superiority over Syrian territory (see Jeremy Binnie, “Israeli officials confirm Syria to get 'good version' of S-300”, Jane's Defence Weekly, 29 May 2013).
The all-round problem
A year ago, many in Israel (as elsewhere) believed that the Assad regime would not last long and that Syria would emerge from the conflict greatly weakened - something Israel could live with, even if it preferred autocracy. Now, it is thought much more likely that Assad will survive and the less Islamist rebels will diminish in power, with European arms arriving too late. The Islamist paramilitaries will survive and probably thrive, though their support from the Saudis and Qataris may not match what the Assad regime receives from Hizbollah and Iran (the latter hugely aided in the process by its close ally in Baghdad).
A detached supporter of Israel might conclude that the probable outcome in such a case - a prolonged standoff between Islamists and Damascus - would be welcome. The problem with it, though, is the uncertainty - the circumstance that Israeli military planners like least of all.
If, later in 2013, Syria's civil war becomes an Assad-Islamist conflict and the Islamists manage to sustain their campaign, then Israel will be in a real dilemma. Would it prefer a renewed and strengthened Assad-Hizbollah-Iraq-Iran entity, or Islamist ascendancy in Syria?
Neither is attractive and this is the real reason for the Israeli government's apprehension over the way the war is evolving. Neighbouring autocrats are OK as long as they do not get too strong, but a regime adjacent to Israel that is at the centre of a Shi'a axis or represents a triumphant Islamist power-base would be most unpalatable. Israel wants to keep the future predictable. But events in Syria are making this ever more difficult.