Lebanon's national unity government collapsed this week after 11 ministers representing Hizbollah and its allies withdrew from the cabinet. The Sunni leader, Saad Hariri, became a caretaker prime minister, and the Lebanese president Michel Suleiman is poised to begin consultations with parliamentary leaders to appoint a new premier.
Hizbollah's walkout was not entirely a surprise: the Lebanese government has been paralysed for months, owing to a UN Special Tribunal investigating the 2005 assassination of the former prime minister, Rafiq Hariri. Lebanon has been on edge since word leaked out that the tribunal is preparing to indict members of Hizbollah for involvement.
Hizbollah, the dominant Shiite political party and militia, has tried to eschew blame by accusing Israel. The group has also pressured Saad Hariri, the slain leader's son, to end Lebanese cooperation with the tribunal and publicly reject its findings. But the younger Hariri, backed by the United States and Saudi Arabia, has refused to disavow the tribunal, which in turn led Hizbollah to topple the government.
Once again, Arab and western leaders find that they must focus their attention on Lebanon, a small country that has long been the staging ground of proxy wars in the region. The Syrian president Bashar al Assad and King Abdullah of Saudi Arabia travelled together to Beirut in July to meet with Lebanese leaders and help calm fears that the country was headed toward civil strife. The visit was meant to show the Arab world that Saudi-Syrian reconciliation is on track. It was also a message from Mr al Assad to Washington: Lebanon cannot remain stable without Syria's tutelage.
The Syrian and Saudi leaders have been negotiating on a compromise over the tribunal for several months, but those talks collapsed last week. That led Hizbollah and its allies to ratchet up the pressure on Mr Hariri.
While both factions have pledged to pursue peaceful paths, political deadlock in Lebanon can quickly devolve into sectarian violence. The last governmental crisis lasted18 months, leaving Lebanon without a president for six months. The stalemate was finally broken in 2008, when Hizbollah ignited the worst internal fighting since the end of Lebanon's civil war.
In response to the then prime minister Fouad Siniora's orders outlawing Hizbollah's underground fiber-optic communication network and his dismissal of a Hizbollah-affiliated security chief at the Beirut airport, the militia dispatched hundreds of heavily armed fighters into the largely Sunni areas of West Beirut. They quickly routed Sunni militiamen, seized their political offices and shut down media outlets owned by Mr Hariri.
Each Lebanese faction accuses the other of serving external masters. Indeed, Lebanon is part of an ongoing proxy war in the region, pitting Iran and Syria (who support Hizbollah and its allies) against the United States, Saudi Arabia and other Sunni Arab regimes (who back Mr Hariri and his coalition of Sunni and Christian parties).
But while external players have a hand in the latest political paralysis, they do not deserve all the blame. The Lebanese need to find a larger political settlement of their own. Otherwise, the Sunni-Shiite rift in Lebanon could explode.
Lebanese leaders need to tackle deeper issues that go beyond the tribunal. Problems are rooted in a 1943 power-sharing agreement installed when the country won its independence from French colonial rule. The system was designed to keep a balance among 18 sects, dividing power between a Maronite Christian president, a Sunni prime minister and a Shiite speaker of parliament. The system was enshrined under the National Pact, an unwritten agreement among Lebanese leaders. Seats in parliament were divided on a 6-to-5 ratio of Christians to Muslims.
The division was based on a 1930s census that showed Maronites as the majority in Lebanon. Since then, the government has refused to hold a new census. By the 1960s, when Muslims began to outnumber Christians, Muslims clamoured for change in the balance of power. When civil war broke out in 1975, the political imbalance helped drive the major sects to form militias. Because of the confessional system, Lebanese political institutions never got a chance to develop and the country remained dependent on the powerful clans and feudal landlords that held sway in much of Lebanon.
The 1989 Taif Accord, which ended the civil war, expanded parliament and divided it equally between Christians and Muslims, and called for all militias to disarm. But Hizbollah remained, branded a "national resistance" movement against the Israeli occupation of southern Lebanon.
While all factions in Lebanon constantly affirm that they will abide by Taif, few acknowledge that the agreement also called for eventually abolishing the sectarian system, although it gave no time frame for doing so.
Even if the two factions can defuse the latest stalemate and reach a compromise on the tribunal and a new government, another political crisis is sure to emerge, unless Lebanon's leaders - and its people - tackle the root causes of the country's instability. Eventually, the Lebanese will have to decide what kind of country they want: one built on sectarian gerrymandering, or a more democratic way of sharing power.
Mohamad Bazzi is a journalism professor at New York University and an adjunct senior fellow at the Council on Foreign Relations