By Tom Pfeiffer and Shaimaa Fayed
CAIRO (Reuters) - Arab governments were swift to condemn Libya's Muammar Gaddafi in February when he tried to crush a popular uprising with machineguns and heavy artillery.
Now, as Syria's Bashar al-Assad uses tanks and live bullets to smash a wave of street protests, the relative silence from Arab capitals speaks volumes.
Such contrasting reactions may seem inconsistent. Syria and Libya are both police states built by former army officers who set themselves up as rivals to oil-producing Gulf states such as Saudi Arabia.
Gaddafi derided the Gulf's conservative monarchies. Assad struck up an alliance with Saudi foe Iran and helps it fund Shi'ite militant group Hezbollah in Lebanon.
But collapse of the Assad government would suggest the domino effect that toppled leaders in Tunisia, Egypt and Yemen has spread from North Africa into the heart of the Middle East, raising the risks for Syria's neighbors.
"The fall of the Syrian regime, along with a fall of the Yemeni regime, would mean a shift of the revolution to a region very close to the Gulf area," said Nabil Abdel Fattah of Al Ahram Center for Political and Strategic Studies in Cairo.
It seemed easier to abandon Gaddafi after Libya burned its bridges with many Arab governments and he turned his attentions south, having himself named King of Kings of Africa.
Syria has used a mixture of direct intervention and quiet diplomacy toward its neighbors to counter multiple threats in a volatile region.
The result is that a future balance of power in the Middle East is hard to imagine without a Syria ruled by Assad.
"Assad may not be the most well-liked of Arab leaders but he's someone who many Arab governments have a working relation with, and in some cases a close relationship," said Shadi Hamid, Director of Research at Brookings Doha Center.
The Assad clan has spent decades cajoling events in the region in its favor through a combination of funding for sympathetic groups abroad and sanctions on others.
That game of influence is starkest in Lebanon, where opponents say it closely manipulates the country's politics in to fit its agenda.
Saudi Arabia accuses Damascus of ordering the assassination of Lebanon's Sunni former Prime Minister Rafik al-Hariri.
The head of the Arab League, Amr Moussa, voiced "worry" in June about the months-long clashes in Syria, but signaled divisions in the 22-member body over how to proceed.
He said Arab states were trying to agree a common position.
"Even Saudi, which has been at loggerheads with Syria for decades, has stayed quiet because if Assad was overthrown that would be another victory for Arab publics that could spill over into the peninsula," said Laleh Khalili, Senior Lecturer at London's School of Oriental and African Studies.
Like many of his neighbors, Assad sits atop an autocratic state that contains a melting pot of religious and tribal groups, many of which traverse boundaries set in colonial times.
Syria's 20 million population is mostly Sunni Muslim but Assad and many senior army figures belong to the Alawite sect, an offshoot of Shi'ite Islam. The country also contains Christians and ethnically is made up of Arabs and Kurds.
Opponents say Assad increasingly relies on loyalist Alawite troops and irregulars known as 'shabbiha' to put down the protests.
For countries like Saudi Arabia, Kuwait and Jordan, an overthrow of Assad could be one Arab revolution too many.
"The fall of the Syrian regime would mean the sectarian and religious balances in the southern region would completely collapse," said Abdel Fattah.
Fear of ending up on the losing side may also be encouraging Syria's neighbors to stay neutral.
Gaddafi had already lost control of eastern Libya when the Arab League came out in support of a United Nations resolution authorizing western-led military action to protect civilians.
Assad's opponents have predicted a national uprising unless the government ends the bloodshed, but some of the demonstrators seem to want reforms, not a revolution, and there is little sign of a reformist government in waiting being formed.
An organised rebel leadership emerged in Libya in just days. Syria's opposition groups are divided over the way forward.
Western governments led by France have condemned the bloodshed in Syria but have shown no appetite for military intervention that could tip the scales away from the government.
"Western powers see Syria as far too central for their stability, which ends up mattering more than their rhetoric on liberalization and democratization," said Khalili. "That is why Israel is also quite silent."
Libya's uprising came weeks after revolutions in Tunisia and Egypt and suggested a democratic tidal wave had began to sweep the region.
That sense of the inevitable took a hit when Bahrain's monarchy smothered a popular uprising with the help of Saudi Arabia's army.
"Arab leaders are still not sure which way the wind is blowing," said Hamid at the Brookings Doha Center. "Assad might still find a way to survive and they don't want to undermine their relationship with him and the people around him."
(Editing by Samia Nakhoul)