BEIRUT—On Thursday night, a team of suicide bombers struck at rush hour in the crowded southern suburbs of Beirut. The attack killed at least 40 people, and would have killed many more had it not been for the bravery of a man who tackled one of the bombers. According to some reports, a third bomber was blown up before he could detonate his weapon.

For a year and a half, the southern suburbs have been relatively safe after a crescendo of attacks in 2013. The last major suicide bombing in Beirut struck near the Iranian cultural center on February 19, 2014. Since then, a combination of factors abated the toll on civilians, although there was a steady trickle of smaller attacks and foiled bombings.

The formula that successfully calmed the situation in Lebanon was built on three pillars: (1) security cooperation between Hezbollah, the Lebanese Army, and the Internal Security Forces; (2) intelligence cooperation between the major state and non-state agencies (General Security, ISF, military intelligence, Hezbollah and others); and (3) a political commitment from bosses of all sects to discourage attacks on civilians, deter jihadis, and pressure targeted civilians to refrain from reprisals.

The fact remains, however, that Lebanon has become embedded in the Syrian war, and already was fully enmeshed in the regional struggle between interventionist powers including Saudi Arabia, Iran, Syria, Israel, and the United States.

Hezbollah’s decision to openly enter the Syrian civil war on the side of President Bashar al-Assad made it inevitable that the war in Syria would reverberate in Lebanon, in one manner or another. Meanwhile, the Sunni community of Lebanon—whose share of the population is shrinking—has suffered a leadership that is inept, corrupt, and fragmented.

These dynamics have created a dangerous impasse. As in 2008, Hezbollah is demanding a greater share of government decision-making power, which from a realpolitik perspective is a winning argument. The Shia proportion of the population has continued to grow, and Hezbollah is indisputably first among equals in Lebanon’s sectarian power-sharing system. It will never be strong enough to dominate the entire country, but today its raw power is unequalled: its base is hyper-mobilized, its militia is stronger than the national army, and it has a symbiotic, possibly controlling relationship with the armed forces and General Security.

And as in 2008, there is standoff over filling the presidency, which has been vacant since May 2014.

Hezbollah’s rivals can convincingly argue that party’s demand for more say over the government is distasteful, perhaps even morally wrong. But Hezbollah holds the winning cards right now, and will likely get what it wants—probably after some avoidable and bloody showdown, like the battles in Beirut and the Chouf in May 2008, which convinced the anti-Hezbollah bloc then that it was too weak to press its demands.

Over the short term (which I’ll loosely define as the likely span of the Syrian war, which will probably last another five to ten years), Hezbollah will remain the preeminent power in a Lebanese system that functions like a mafia oligarchy, controlled by a small number of undemocratic, unrepresentative leaders whose primary interest is enriching themselves and perpetuating their power. This cult-of-personality/balance-of-power bonanza of corruption and misrule has proved highly elastic.

In its favor, the system prevents any single strong group, even Hezbollah, from dominating the others outright, and for twenty-five years it has served as a powerful buffer against a renewal of civil war. Its downside is that Lebanon’s sectarian power-sharing deal has evolved in true mafia style into a free-for-all for the dons and their foot soldiers, with literally nothing left for the citizens of the country. A poorly run failing state in the 1990s, Lebanon has slipped into a worse and worse condition such that today, almost nothing functions.

There is no president, and parliament can’t even meet to authorize disbursement of funds—which would mostly be siphoned off in corruption and patronage schemes anyway. Garbage processing shut down over the summer, and today Beirut’s trash is spirited out of wealthy neighborhoods and dumped in rivers, alleys, and the poor quarters while politicians fail to agree on a way to handle the nation’s waste. Bribes and inefficiencies are ubiquitous, affecting everyone; just this week, in fact, corrupt customs officials held up a set of house keys my friend had express-mailed back to me until we paid a $15 “tax” charge. Some citizens find it impossible to obtain basic services from the state, such as the issuing of an ID card or the registration of a contract. Even those willing to pay bribes sometimes can’t even cut through the mess.

In this environment, many factors augur poorly for the long term.

The conflicts in the Levant and throughout the Arab world are fully regionalized, connected to a web of external actors, transnational movements, and activist governments. Syria and Lebanon are both organic parts of a regional conflict, prey to local dynamics as well the Iran-Saudi regional struggle.

Hezbollah’s short-term position remains secure, because its base supports it more strongly than ever. Over the long haul, however, it has lost any credibility as an umbrella actor with a unifying national project in addition to its own agenda. Hezbollah, despite its history galvanizing resistance to Israel, today has been reduced in the eyes of many of Lebanese and regional observers to another parochial sectarian group that works in lockstep with a foreign patron.

Sunni leadership has fragmented, leaving its constituency vulnerable and exposed. As a result, many Lebanese Sunnis operate without a sense of political cover, and in many areas like the impoverished northern district of Akkar, without even the minimal services that most other Lebanese can enjoy. This disarray has left a vacuum in which extremists such as ISIS can operate and recruit, and in which Lebanon’s many political crises could climax into a destabilizing game of chicken.

None of the status quo actors want a civil war, which is the most compelling reason why even if today’s breakdown is resolved by a militia showdown, the violence is likely to be contained. Lebanese factions who want to shoot it out have ample opportunity to do so across the border in Syria.

Sometime in the next year or two there will be another deal like the one negotiated in Doha in 2008. That accord postponed a reckoning and committed Lebanon to a nasty bargain: a sloppy simulacrum of peace in exchange for a continuation of the warlord oligarchy. Lebanon’s blueprint forward is crisis, breaking point, and another version of the same bad compromise that has survived in various guises since the 1943 national accord.

But the country that set the regional standard for a functional failing state is failing more than ever before. Brand Lebanon is broken, and the country’s major political parties own its misrule. That means Shia Hezbollah and its allies, and Saad Hariri’s Sunni Future Movement and its allies, are responsible not just for keeping a tense and violence-wrecked country from sinking into violent strife; they’re also responsible for the fact that nothing in the country works, for the failure of the government to deliver reliable electricity, water, or policing a quarter century after the end of the civil war, despite Lebanon’s obvious wealth and human talent.

In the long term, Lebanon will have to negotiate an entirely different system that creates a new level of accountability and representation for citizens. Failing that, Lebanon needs to find a way to function technically at the level of much poorer but better organized states in the Middle East North Africa region, such as Jordan and Egypt. Generations of corruption and mismanagement have driven Lebanon’s expectations to an abysmally low point, of which the limping state still falls short. Until that underlying failure to govern is resolved, Lebanon will simply cling on from crisis to crisis.