Lebanon's former prime minister, Rafik Hariri, was killed by a huge explosion near downtown Beirut in February 2005. Since then, the country has seen – in addition to the Israeli bombardments of summer 2006 – more than a dozen other mysterious assassinations. Nearly all those killed were, like Mr. Hariri, outspoken critics of the strong role that Syria plays inside Lebanon.

Ever since 2005, analysts have speculated that Lebanon might be headed back into the civil war from which it extricated itself, with much difficulty in 1989.

But this has not happened. Why?

My main point of comparison is April 1975. I had been in Lebanon for just a few months by then, at the beginning of my journalism career. That month, Falangist Party militiamen in a Beirut suburb caught a bus full of "hated" Palestinians in an ambush and shot 27 men dead. The whole country was a tinderbox, home to six or seven armed factions: some Palestinian, some Lebanese.

The April ambush proved to be the "trigger" that tipped Lebanon into all-out civil war. During the years that followed, it was my sad task to report on the many grisly turns the war took. I investigated massacres. I dodged bullets, mortars, and artillery. I interviewed political leaders from all sides, the survivors of atrocities, and families trying to survive in basement shelters. I saw the country fall apart.

In 1981 I left. But the war continued until 1989, when the efforts of Saudi and other diplomats and the war weariness of most Lebanese produced the Taef Accord, an agreement that finally allowed calm to be restored and rebuilding to start.

When I was in Beirut this January, I found the atmosphere in most – but not quite all – of the city noticeably calmer and more relaxed than it was in April 1975. Restaurants were booming. Cafés and cinemas stayed open late.

I asked Lebanese friends whether they feared the civil war might reignite. Most shrugged, saying they felt disaffected from all the political parties. The passion with which Lebanon's people engaged in national politics back in the 1970s seemed largely absent.

In only two sectors were political feelings running high: among the country's semiprofessional politicians, across the political spectrum, and among both the leaders and the public in the Shiite Muslim community, the country's largest.

The physically devastating air attacks that Israel launched against Lebanon's Shiite areas in 2006 seemed to have left most Shiites fiercely loyal to the community's dominant party, Hizbullah, which they see as having stood up for their interests. Hizbullah's militia is still, by far, the best-armed militia in Lebanon.

Lebanon is full of paradoxes. On Feb. 14, Beirut hosted two huge public gatherings, organized by diametrically opposed forces. In the morning there was a large, open-air commemoration of the third anniversary of Hariri's killing, and in the afternoon Hizbullah hosted an equally large, mainly indoor, funeral for its key military operative, Imad Mughniyeh, killed in Syria two days earlier. Despite the potential for clashes that day, there were none.

Hizbullah leader Hassan Nasrallah has voiced fiery threats against Israel and the United States, most recently in response to Mr. Mughniyeh's killing. We should take those threats seriously.

But we should also note that inside Lebanon, Hizbullah and many other factions have all worked hard together to defuse potential points of conflict. They did this in late January after clashes between Lebanese Army troops and Shiite groups protesting price hikes. And they did it again this week, after turf clashes erupted between Shiites and Sunnis in southwest Beirut.

In the West, Hizbullah is known mainly for its acts of anti-Israeli and anti-Western violence. But in Lebanon, it's a full part of the political game, having run – and won – in parliamentary elections since 1992. (Also significant: Much of its political weight comes from its alliance with the Free Patriotic Movement, whose members are nearly all Christians.)

So here is the biggest paradox of all. Lebanon is mired in a tough constitutional crisis. Parliament hasn't had a quorum for months, and there has been no president since November. Violent incidents of mysterious origin keep occurring. But still the country hasn't plunged into civil war.

Again, why? For a number of reasons: memories of how bad the last civil war was; a lessening of the power of ideology and the rise of new, sect-crossing economic concerns; the absence of the Syrian troops who were once a lightning rod; and the persistent efforts to contain and defuse tensions that many Lebanese leaders themselves have undertaken.

Can these factors continue to keep Lebanon safe from civil war? Let's hope so.