• Close contact with US forces in the Saudi desert convinced the Syrians that the qualitative edge of US weaponry would put Syria at a permanent strategic disadvantage.

This sombre realisation brought about three important changes in Syrian posture:

• a preference for diplomacy;
• a quest for guarantees for its hegemonic ambitions over Lebanon; and
• the maintenance of the asymmetric option of war by proxy through the strengthening of Hizbollah in southern Lebanon and the slow bleeding of Israel's forces there.

The Taif agreements secured Syria's interests in Lebanon; the US diplomatic offensive that followed Desert Storm brought the Syrians to the Madrid conference and into direct negotiations with Israel; and the Lebanese quagmire enabled Damascus to maintain pressure on Israel.

However, in 2000, the collapse of Israeli-Syrian negotiations, Israel's unilateral withdrawal from Lebanon, and President Hafez al-Assad's death changed the situation. His son Bashar was absorbed in consolidating his power and the disappearance of pretexts for a proxy war in southern Lebanon left Israel's northern frontier even quieter. However, the outbreak of the second intifada offered the regime another conduit for asymmetric warfare against Israel via support for Hamas and Islamic Jihad.

Eroding equilibrium. Several factors changed this fragile balance further starting from 2004:

• Israel's crushing of the intifada reduced the ability of Syrian proxies to damage Israel.
• However, Israel's focus on the intifada had also meant less attention on the northern border, where Hizbollah had six quiet years to build up its military might.

The Lebanon war further undermined the uneasy equilibrium:

• The inconclusive outcome exposed the degree of Syrian-Iranian cooperation and eroded Israel's deterrence, especially in an asymmetric type of conflict
• Though the deployment of an enhanced UN force made further fighting unlikely, there have been continuing rumours of a fresh round involving Israel and Syria.

Confused signals. The rhetoric of the past year offers conflicting signals:

• Syria has reiterated its desire to negotiate a separate peace with Israel. Indeed, there have been persistent rumours of 'secret' talks taking place. However, it has also made it clear that it viewed war as a possibility, if diplomacy were to fail . The Israeli intelligence community disagrees about Syrian intentions.
• Israel has been watching Hizbollah's rearmament north of the Litani river, and has received reports of Iranian help for Hizbollah to create a Shia continuum between the south and the Bekaa Valley through land purchases, infrastructure projects and new fortifications.
• There are also continuing reports of arms shipments to Hizbollah and of further integration of Hizbollah and Syrian and Iranian forces. Much of this integration relies on procurements from Russia, which, following a trilateral deal reportedly struck in 2000 with Syria and Iran, is providing sophisticated weaponry to the two countries.

Israeli concerns. After the 2006 war, Israel's initial assessment was that Syria might try to replicate Hizbollah's successful combat techniques in an attack on the Golan Heights, to secure enough territorial gains and inflict enough losses on Israel to force a later diplomatic agreement to Syria's advantage. Israel's concerns are now worsened by the arms deals. The return of Russian influence in the region — made most manifest by its establishing a naval base in northern Syria — has given Syria access to the kind of sophisticated weaponry its military was lacking since 1991. Thus the developments of the last year have improved Syria's choices, making it possible for Damascus to pressure Israel through both conventional and asymmetric means.

Israeli sources offer additional reasons for possible war:

• Syria's position as an isolated regime makes it unlikely that it will accede to a peace accord with Israel, unless it can dramatically improve its strategic position first.
• If Israel were to return the Golan Heights now, Syria would have to accept full normalisation, severing its links with Tehran and ending support for Palestinian organisations in Damascus.
• Additionally, a deal with Israel might require a significant opening up of Syria's economy and it could therefore undermine the regime's grip on the country Thus, Syria would be foolish to sue for peace, unless strategic circumstances are dramatically modified to its benefit first. A surprise attack on Israel might achieve this.

A clear indication of how seriously Israel takes this possibility is the restraint Israel has so far exercised in the south. Since unilaterally disengaging from Gaza in August 2005, Israel's southern communities have suffered Qassam rocket attacks from Gaza, and Hamas has taken control of Gaza. However, Israel has so far avoided launching a massive ground operation in Gaza, in part out of concern about a sudden flare-up in the north. Its forces have maintained a constant state of alert and engaged in several high-profile military exercises on the Golan.

Speculation. As last week's still mysterious Israeli mission over Syria indicates, the potential for conflict is high:

• Israel's officialdom has been uncharacteristically tight-lipped about the nature of the operation.
• The official Syrian condemnation also lacked details of the attack and the damage, perhaps to avoid feeling obliged to respond to avoid the humiliation.

This uncertainty lends itself to speculation:

• A plausible explanation is that Israel, concerned about its eroding deterrence, has undertaken a risky demonstrative operation to re-establish its supremacy without precipitating a major confrontation.
• Syria's relatively restrained response suggests that Damascus got the message and for the moment will refrain from escalating.

Outlook. There are plenty of risks ahead:

• Domestic tensions in Lebanon could precipitate a crisis over the presidential election . The ensuing power vacuum could leave more room for Hizbollah mischief in the south.
• The Qassam rocket attacks will sooner or later will provoke a harsh Israeli military response, which Hizbollah and Syria might exploit to open a second front in the north — as happened last summer.
• Damascus will probably find itself cornered, sooner or later, by the pressure mounting from the international tribunal established to try the killers of former Lebanese Prime Minister Rafik al-Hariri.

Any of these could create an excuse for military action, which would most likely erupt along the Israeli-Syrian front.