Russia has strong material and political incentives to support the status quo in Syria. Assad's father formed a strategic alliance with the Soviet Union in 1971, and since then Syria has been Russia's steady – and now sole – client state amid the shifting alliances of the Middle East.
Russia is Syria's principal armorer, with an estimated $5 billion in outstanding weapons contracts, mainly advanced anti-aircraft systems, coastal defense missiles, and jet trainers. Russia also has the use of a naval re-supply center in the Syrian port of Tartous, which is the only Russian military base outside the former Soviet Union. Experts say there is about $15 billion in more traditional economic contracts, including construction and energy projects by big Russian firms. About 100,000 Russians reside in Syria, which will present the Kremlin with a logistical nightmare if they have to be evacuated.
Another key Russian concern, which has received very little attention, is the intensely conservative attitude of the powerful Russian Orthodox Church, which sees itself as the protector of Syria's beleaguered Christian minority, comprising about 10 percent of the population. "The Orthodox Church presses very heavily on the Kremlin to defend Syria's Christians, whose safety has been assured by the Assad regime all these years," says Vladimir Yevseyev, an expert at the official Institute of International Relations and World Economy in Moscow. "Russia's interests at stake here are more geopolitical than they are economic."