Syria has more than 21 million people (Lebanon has 4 million; Israel 8 million).
Saudi Arabia (27 million), Iraq (30), Turkey (75), Iran (78), and Egypt (81).
Saudi Arabia is 97 percent Sunni, Egypt 90% Sunni, Syria 75% Sunni.
The Sunni majority in Syria -- and all Sunni governments in the Arab League -- want to overthrow the ruling Alawites (a tiny sect of Shiites) and their Christian allies (10 percent).
Democracy in Iraq gave the 65 percent Shiites new control over the secularists who favored the 30% Sunni and 5% Christians.
Democracy in Egypt will hurt the 10 percent Christian Copts who were favored by the secularist leaders Mubarak and Sadat.
Democracy in Turkey is replacing the old secular traditions of Kemal Ataturk (d. 1938) with Sunni Islam dominance.
Lebanon has not had a census since 1932: Christians 40%, Sunni 28%, Shiite 28%. This split would be tipped if half a million Palestinian refugees (97 percent Sunni) were allowed citizenship. The present Syrian government (and Iranian funds) aids Shiite Hezbollah emergence in Lebanese government.
Supporters of Syria's government are Shiite Iran along with Orthodox Christians -- both oppose another Sunni-dominated state.
The Sunni Arabic Saudis are all for attacking the Persian Shiites of Iran (90 percent of the population, with 8 percent Sunni).
The Russian government -- which blocked the UN's condemnation of Syria -- promised its Russian Orthodox bishops that its foreign policy will include the defense of Christians in the Mideast. This was the major cause of the pre-Communist Russian Crimean War against the Ottomans (the former Turkey, et al).