Syrian President Bashar al-Assad has few good options for military retaliation after Israel's air strikes over the weekend but the attacks could redouble support from his regional allies Iran and Hezbollah.
Assad, already battling rebel fighters who have seized large parts of his country and killed many thousands of his troops, can ill afford to confront the region's dominant military power in a devastating and likely one-sided war.
And his allies in Iran and Hezbollah are also wary of starting a new battle which would divert from their determined efforts to keep their strategic ally in power in Damascus.
"Significant military action is unlikely," said Paul Salem, director of the Carnegie Middle East Centre. "Syria, Hezbollah and Iran are not interested in opening another front when clearly their main battle is for the Syrian regime to survive."
Israel's twin air strikes within 48 hours shook Damascus, sent pillars of flame into the night sky and killed dozens of soldiers.
The war planes struck Assad's elite troops in the valley of the Barada River that flows through Damascus and on Qasioun Mountain overlooking the capital, said residents and opposition sources. Targets included air defenses, Republican Guards and a compound linked to chemical weapons.
The Syrian Observatory for Human Rights said at least 42 soldiers were killed and 100 more were missing. Other opposition sources put the death toll at hundreds of troops. A Western security source said the attacks targeted Iranian missiles intended for Hezbollah which could strike Tel Aviv.
Both Damascus and Tehran have hinted at a tough response.
Syria's information minister said the attacks "opened the door to all possibilities". Iran's foreign ministry spokesman warned of a "crushing response".
Syria did not retaliate in 2007 when Israeli jets struck a suspected nuclear facility, nor in January this year when they bombed a suspected missile convoy. On each occasion Damascus said it would choose the time and place to respond.
But the scale of the latest operation will pile pressure on Assad to respond, "not only to save face but also to maintain credibility at home and in the region," said Fawaz Gerges, director of the Middle East Centre at the London School of Economics.
"That's where Assad's predicament is - what do you do, given the limited options?" he said.
A GOLAN FRONT?
Two years into the uprising against his rule - which has spiraled into a civil war pitting mainly Sunni Muslim rebels against a president from Syria's Alawite minority sect - Assad still has regional supporters.
As well as Iran and Hezbollah, Damascus also has links to some militant Palestinian groups and has a degree of support from neighboring Iraq's Shi'ite-led authorities, who have turned a blind eye to Iranian weapons cargoes flown across Iraqi airspace, according to a senior Iraqi Shi'ite leader.
Syria's pro-government Al-Ikhbariya television gave an indication of what Assad might be considering, quoting unnamed sources who said that Syrian rockets were ready to strike targets inside Israel in the event of any new attack.
It also said Syria had given the green light to Palestinian factions to carry out operations against Israel from across the Israeli-occupied Golan Heights.
However, neither of those warnings have been spelled out publicly by Syrian officials, and any direct Syrian rocket fire on Israel would be likely to provoke an overwhelming Israeli response.
Perhaps ironically, the step that Assad could take in the Golan that might most alarm Israel would be to retreat from it.
Through four decades of official hostility with Israel, Assad and his father before him kept the Golan Heights frontier quiet. Were Assad to pull back troops, Israel is worried that the heights it captured from Syria in 1967 could become a springboard for attacks on Israelis by the jihadi rebels who are currently battling to topple Assad.
"I would not be surprised if the Assad regime begins the process of pulling out its forces from the Golan to Damascus," said Gerges. "The (rebel) Nusra Front and other groups are preparing themselves for the ultimate war against Israel...so this would create a strategic predicament for Israel."
A Western diplomat in the region said that if the Nusra Front gained territory on the Golan Heights it would inevitably suck Israel deeper into to conflict.
"They will not accept that Islamist extremists gain ground," he said.
Hezbollah, Assad's Lebanese ally which fought a 34-day war with Israel in 2006, has maintained a resolute silence over the Israeli raids on Damascus.
Israel believes Hezbollah has built up an arsenal of about 60,000 missiles and rockets, making it potentially a more formidable foe than in 2006, when the militant group fired 4,000 missiles into Israel.
"Hezbollah has to tread carefully because they can't afford to be fighting in Syria (against the rebels) and provoking Israel on the Israel-Lebanon border," said another diplomat.
The militant Shi'ite Muslim group, which is accused by Bulgaria of a bombing which killed five Israeli tourists in a Black Sea resort last year, could seek to strike Israeli targets abroad instead of seeking direct confrontation.
But Gerges said the most likely response would be to reinforce its backing for Assad.
"Both Hezbollah and Iran will respond to Israel's escalation by deepening their own involvement in Syria," he said. "Israel's logic says: 'We will not allow any transfer of advanced weapons to Hezbollah'. If you deepen Hezbollah and Iranian involvement in Syria, you are punching holes in this logic."
That deepening support from Assad's allies, matched by the growing support from Gulf Arab countries and Turkey for his rebel foes, could push the Syrian crisis - which has already killed 70,000 people according to the United Nations - one step closer to regional conflict.
"The risk factor has become much more acute in recent weeks," the second diplomat said, referring to the prospect of a broader war.
Assad has vowed to defeat the rebels and his troops have launched recent counter-offensives around Damascus, the central city of Homs and the coastal province of Banias, where activists said his forces killed scores of people.
Israel cannot assume that the Syrian leader will remain passive if it continues its attacks inside Syria's borders, the former director of Israel's espionage agency Mossad said.
"The broader the strike, the greater the chance that Assad will have no choice to respond," Danny Yatom told Israel Radio. "The Syrians too have limits. And the limit is not necessarily a blow to Syrian sovereignty, but rather a blow to Syrian honor."
Additional reporting by Samia Nakhoul in Amman, Dan Williams in Jerusalem, Suadad al-Salhi in Baghdad and Yeganeh Torbati in Dubai; Editing by Peter Graff