The crisis has been building since Oct. 1. On that morning, Marwan Hamadi, a Lebanese parliamentarian, nearly was killed as his Mercedes emerged from the underground garage of his apartment tower and rolled down a steep hill toward the corniche. Two men were watching from behind, seated on stone steps that lead to a private school. A 26-lb shaped charge of C-4 explosive planted in a parked car blasted the departing Mercedes, instantly killing a guard seated in the rear. Injured, Hamadi survived--probably saved only by the bomber's presumption that he would be in the guard's place.

All of Lebanon instantly came to the same conclusion: Syria was defending its hegemony over its smaller neighbor in the traditional way: by terror. Hamadi is a top aide to Druse leader Walid Jumblatt. And Jumblatt's party recently had walked out of the government to protest a constitutional amendment, rammed through by Syria, which gave Lebanese President Emile Lahoud a third term. The murder case never was solved: a VHS tape of the suspects, recorded by the private school's closed-circuit security cameras, mysteriously disappeared from police custody. History, though, fueled the widespread assumption. Jumblatt's father was killed in ambush in 1977 when he bucked orders from Syria.

But the rules of the game already had changed. Syria's move to impose Lahoud, a former general, came amid growing international pressure on him to back off from Lebanon. For once in the post-Iraq War Middle East, Washington had joined with London, Paris, and Bonn to protect the region's most vibrant democracy outside Israel. France holds Lebanon dear as a Francophone former protectorate; Washington wants to tame an implacable foe of Israel and the U.S. occupation in Iraq. In September, they backed a U.N. Security Council resolution that threatens sanctions unless Syria pulls out 14,000 troops that stayed in Lebanon after a 14-year civil war ended in 1990. (The U.N. sanctions would be in addition to financial sanctions already imposed by the Bush administration on Damascus last May.) After the Hamadi attack, they backed that up by bluntly warning Syria's President Bashar Assad that they'd hold him responsible for any more such assassination attempts.

In Lebanon, the result has been unprecedented public criticism of Syria. Opposition politicians told of answering to a Syrian intelligence officer resident in a small town near the border. After one final showdown with this Syrian proconsul, Prime Minister Hariri resigned. This spring's electoral campaign for April and May elections took on the air of a people-power movement. Syria found itself fighting along a flank--territory it never accepted as being a foreign country after partition by France.

The first battlefield: the rules of political engagement. Parliament is wrestling over a draft electoral law that would gerrymander districts in opposition strongholds and create such curious loopholes as the possibility of canceling the vote result if parliament deems independent press coverage to have been biased. Syria's foes also are seeking international pressure to overcome the government's refusal to accept international observers in the Bekaa Valley and South Lebanon, controlled by armed militias loyal to Damascus, including the Iranian-linked Hizbullah. People looked to the example of Ukraine's re-vote as an example of how public protest can overturn an unfair ballot. Hamadi's brother Ali, a leading television commentator, switched his trademark red tie to the orange adopted by Ukrainian demonstrators.

In the short term, Hariri's assassination would seem to seal electoral victory for Syria's allies in Lebanon. Hariri's 26-member parliamentary bloc was seen as crucial to an opposition victory. And although France promptly called for an investigation of the murder--and the White House called it a reminder that the Lebanese people must be able to build a future "free from Syrian occupation"--car bombings leave few clues. Syria also denounced the killing--and denied any involvement. A previously unknown group, "Victory and Jihad in Greater Syria," claimed responsibility.

Still, Syria can only lose in this confrontation. If Damascus steals the election, the Security Council has another, tougher, resolution ready. The Hariri killing could bring this off the shelf even sooner. If Syria's allies win the elections cleanly, the September Security Council resolution still stands. If the opposition takes power, Syria's only fallback will, once again, be raw force. And the September resolution could badly damage the economy of a country almost without allies. In Moscow last month, Assad won the forgiveness of most debts his father, former president Hafez Assad, ran up while buying jets and missiles during the Cold War. But as Ukraine demonstrated, Moscow no longer has the clout to play spoiler. Even with Hariri dead, this could be a Beirut Spring.