There was once a time in Lebanon’s history when every major faction in its political system (the Hariri family, the Lebanese Armed Forces, Hezbollah, and the Maronite Catholic community) decided to throw down their weapons in order to forge a national unity government. Hezbollah and the Sunni community led by Prime Minister Saad Hariri, bitter enemies in the past, were able to cast aside many of their differences in the pursuit of this goal. In fact, the national unity government that would result from this cooperation boded relatively well for Lebanon. Differences over ideology and policy were still prevalent, but those differences were being played out in the cabinet, not on the streets.

Unfortunately, this era in Lebanon’s history has now eroded. On January 12, Hezbollah lawmakers and Hezbollah sympathizers in Saad Hariri’s administration decided to pull out of the government altogether, giving Lebanon watchers another bout of worry that the entire country may be quickly coming apart at the seams.

The issue that prompted the pullout is one that has hovered over Lebanon like a dark cloud for the past five years: the International tribunal tasked with investigating the killing of former Lebanese Prime Minister Rafiq Hariri.

While the work of the tribunal has proceeded at a slow pace, analysts monitoring Lebanon expect indictments to come out soon. Western and Arab officials are bracing for the ruling, which will probably charge members of Hezbollah with at least partial responsibility for Hariri’s death. Yet the cost of issuing the indictments may in fact come at the expense of Lebanon’s national security: something that ordinary Lebanese are all too accustomed with.

It was quite clear at the beginning of the investigation that Hezbollah would not, under any circumstances, respect the international tribunal. Hezbollah has launched verbal attacks against the tribunal in the past, describing it as an Israeli plot to destroy its movement. Sheik Hassan Nasrallah, the leader of Hezbollah, has vowed to “cut off the hand” of anyone who attempts to arrest a member of Hezbollah for Hariri’s murder.

The departure of Hezbollah from the Lebanese government is already being viewed by American officials as a provocation meant to plunge Lebanon into another round of sectarian violence.

But in reality, this move may simply be Hezbollah’s way of demonstrating to the United States and its moderate Arab allies in the region that it has both the power and the influence to rewrite a chapter in Lebanon’s tense political history. Washington may not like what Hezbollah’s political wing is doing, but the fact remains that the White House doesn’t possess any leverage to stop Hezbollah from doing what it wants to do.

How the prime minister and his political allies respond is now the next stage in the game.  Hariri has already been asked by the Lebanese president to remain in a caretaker role, at least keeping some semblance of governance in place — even if the Lebanese government is usually gridlocked on a good day.

Qatar, a tiny Gulf Emirate that negotiated an agreement between rival Lebanese politicians only two years ago, may feel tempted to renew its role as a power broker. Demonstrations in support of Hezbollah and demonstrations in support of Hariri will ensue on the streets of Beirut, which could quickly turn sectarian if the situation is not kept under a modicum of control. (Hezbollah is the main representative of Lebanon’s Shia, while Hariri is often regarded as the de facto leader of Lebanon’s Sunni community.)

Meanwhile, the most the United States can do is sit back, make some telephone calls and hope for the best.