As I read the record, Syria provoked the initial crisis in fall, 2004, by overplaying its hand and making the Lebanese accept its choice for president, Gen. Emile Lahoud, for a further 3-year term. PM Rafiq al-Hariri resigned over this heavy-handed interference and looked set to challenge Damascus in the spring, 2005 elections. He was then assassinated in February, 2005. The assassin was himself a Sunni fundamentalist, but the operation may have been encouraged by Syrian or pro-Syrian actors.
The assassination of Hariri touched off a mass protest demanding that Syrian troops finally leave Lebanon (a peacekeeping force came in in 1976 with a US green light, during the civil war). The Syrians were supported by the Shiite Hizbullah, which staged demonstrations nearly as big as those of the pro-Hariri forces. Hariri was a Sunni, but the coalition put together after his death included Christians and Druze, as well.
Syria did withdraw. At that point, Lebanese politics became less polarized, and elections produced a national unity government that izbullah also joined.
But then in summer of 2006, Israel launched its long-planned war on little Lebanon, wreaking vast destruction on south Lebanon and on the southern slums of Beirut where Hizbullah was based. Israeli policy was in part to attempt to divide and conquer the Lebanese by making the reform government of Fuad Seniora attempt to disarm Hizbullah, which maintains a small paramilitary force of 3,000 to 5,000. The Lebanese government is too weak to take on Hizbullah, but members of the March 14th reform movement did lay the blame for the war at its feet.
As a result, Hizbullah has pulled out of the government. With Gemayel's assassination, the government will fall if it loses even one more cabinet minister. Worse, the society has now been economically devastated by Israeli bombing raids and is increasingly polarized. The Olmert government's plan for the second Lebanese civil war seems increasingly plausible. Syria has stupidly played into Israel's hands in this regard. The Lebanese themselves are in danger of once again allowing themselves to be used as proxies by people like Bush and Asad and Olmert. The positive achievements of the national unity government of summer-fall 2005 have been undone. Lebanon is on the brink.
This is all in part because the Bush administration permitted Israel to bomb Lebanon in an effort to destroy Hezbollah. And that was the result of a Bush administration foreign policy that is pre-occupied with terror (even terror focused at Israel), is unilateral in it's approach, is simple-minded in it's doctrine, and is ineffective in nearly every application. And while the consequences are certainly detrimental to our own national interest, the worst of the effects will continue to be felt by people who had no say in our policy at all: first the Iraqis, and now the Lebanese.