The Iranian- and Syrian-backed militia Hezbollah just took down Lebanon’s government. It did so without firing a shot—which, so far as I know, is unprecedented for a terrorist army—yet its action could be just the nonviolent prologue to a deadly serious, possibly region-wide crisis. Eleven ministers from Hezbollah and its aligned parties resigned from the Lebanese cabinet, leaving the government short of the number it needed to continue.

At issue was the United Nations Special Tribunal for Lebanon, which is expected to indict Hezbollah in March for assassinating former prime minister Rafik Hariri with a car bomb in 2005. Hezbollah’s secretary general, Hassan Nasrallah, had been pressing the current prime minister, Hariri’s son Saad, to condemn the tribunal and preemptively discredit the looming indictment, but Hariri refused. He and his allies in the “March 14” coalition—named after the date when a million or more people demonstrated in central Beirut against the Syrian occupation in 2005—have surrendered to Hezbollah on several points of contention, not the least of which was the number of ministers that Hezbollah would get in the cabinet. But the son of the slain former prime minister would not surrender on this. He’d rather lose his government and his job than give even tacit approval to Hezbollah’s ridiculous story that the Israelis were behind the attack that killed his father, one of the most liberal prime ministers in the Arab world’s history.

At the time of the bombing, most observers, including me, assumed that the culprit was the Syrian military regime then occupying Lebanon. Hezbollah, while certainly capable, had less motive. In hindsight, however, it’s obvious that Hezbollah should have been on a short list of suspects. It is, after all, a terrorist organization. The Party of God has expressed its loathing of the UN tribunal ever since the investigation was authorized in 2005, long before anyone talked seriously about accusing Nasrallah or any of his lieutenants.

Since the Lebanese government refused to discredit the tribunal, Hezbollah and its partners—their own coalition is called “March 8,” after the date of a pro-Syrian rally in 2005—simply upended the chessboard, hoping to hold more power in a new, reshuffled cabinet with a different prime minister. You might give Nasrallah a little credit for dissolving the government without violence, but don’t expect Hezbollah’s restraint to last forever if the country remains deadlocked. “The Syrians will now try to influence the formation of the new government,” Lebanese scholar and political analyst Tony Badran says, “in the hope of excluding Hariri’s allies, such as the Lebanese Forces, and impose other conditions aimed at neutering Hariri’s power and increasing its own grip on the various levers of power in the country.” But what if the Lebanese Forces—a Christian party that was once itself a militia—and Hariri refuse to surrender to Syria’s and Hezbollah’s demands? There is no good reason to believe Nasrallah won’t resort to violence, as he has in the past, if Hariri and his partners remain defiant.

A compromise might be reached within days, but street clashes or even a war is possible, too. A short internal war could be contained inside Lebanon, but it would be considerably more difficult to prevent a long one from spreading. As British foreign secretary William Hague put it on Wednesday, “This is an extremely serious development which could have grave implications for Lebanon and for regional stability.” Other Middle East countries could easily get sucked in whether they want to or not. The Israelis, who know this better than anyone, have placed their army on high alert in the north along the Lebanese border.

Ever since the 1970s, Lebanon has been a place where the Middle East fights its wars. Syria, Iran, Saudi Arabia, and Israel have stakes what happens there. All either use or have used local sectarian-political groups as proxies against their regional adversaries. (So have France and the United States.) The Middle East’s critical Sunni-Shia fault line runs right through Beirut: each community in Lebanon is roughly equal in size, with Hezbollah representing the Shia and Hariri the Sunnis. The ancient conflict between Persians and Arabs plays itself out in Lebanon, too. Nasrallah is Arab, just as Hariri is, but Hezbollah is the tip of the Persian spear in Iran’s imperial drive for dominance in the region. The West has interests there, for Lebanon is a geopolitical “swing state” between the so-called “moderate” Arab states and the region’s extremists. The Arab-Israeli conflict has been a destabilizing force in Lebanon since the 1970s, and wars between Israelis and Arab terrorist groups in Lebanon have exacerbated that region-wide conflict repeatedly. And the front line in the looming Iranian-Israeli conflict, which could set fire to the region as no war has done for decades, is for all intents and purposes the Lebanese-Israeli border.

Predicting what happens next is impossible. The Lebanese are masters of compromise, so there’s a decent chance that this will blow over soon. But because the fight over the tribunal is a regional affair rather than a local one, the smart money is on an increase in temperature. This is the Middle East, after all.