Lebanon is one of the few Middle Eastern countries where large Christian and Muslim populations coexist in a secular state. How long can this remain so? With the Muslim Brotherhood assuming power in Egypt, and Syria dissolving into a civil war with overtly religious dimensions, the Arab Spring has appeared to shed the secular character that Western audiences originally found so appealing. Lebanon is rife with contradictions and tensions, and the deadly October 19 bombing in the Beirut neighborhood of Ashrafiyeh—a charming, tree-lined Christian district which I frequented often during a five-month stay in the country earlier this year—suggests a bleak path forward for a nation whose pluralism was celebrated by Pope Benedict XVI during his visit in September.

Benedict's three-day visit to Lebanon came at a delicate moment in the Arab world, with the notorious YouTube video "The Innocence of Muslims" sparking riots, and terrorists attacking the American consulate in Benghazi, Libya. The pope dedicated much of his visit to speaking on the need for peace between Christians and Muslims—a message aptly broadcast from a country whose constitution guarantees power to each of its major religious groups. Benedict praised Lebanon's pluralistic government for advancing "coexistence and respectful dialogue between Christians and their brethren of other religions." Yet even as he presided over an open-air Mass at Beirut's City Centre Waterfront, where hundreds of thousands of Lebanese citizens attended in a display of Christian-Muslim unity, angry rioters in the northern city of Tripoli protested his visit and the video.

Those divergent public actions reflect the tenuous and contradictory social order of modern Lebanon as I experienced it while studying there for the spring 2012 semester. When the country's devastating civil war ended in 1990, foreign imports and investment flowed back in, and Beirut attempted to reclaim its former status as a cosmopolitan European enclave in an Arab world. At first glance it emanates a deceptive glamour. In reality it quickly became a playground city predicated on corruption and graft. Prime Minister Rafiq Hariri founded a construction firm, Solidere, and used it to gentrify select sections of the city, even as the rest of the country's infrastructure languished and Lebanon plunged into debt. The crown jewel of postwar Beirut, the City Centre Waterfront, is designed to resemble Paris, but its sparsely filled residential and retail spaces resemble an empty film set. The European-level prices charged in Hariri's downtown marginalize the vast majority of the population, leaving a small group of urban elites, wealthy vacationers from neighboring Arab states, and First World travelers like me to enjoy the city's showy prosperity.

Most of Beirut, by contrast, is a sea of squat, flat-roofed apartments. Hordes of unemployed twenty-somethings sit in cafes all day. Laws are often ignored because there is no real enforcement; no consequences attach to violating traffic laws or walking around the city raucous and inebriated. The soldiers posted on every block lean idly against a wall texting, M-16s dangling at their sides like forgotten playthings. One night a gunfight broke out just outside the restaurant where I was sharing dinner with friends. As the other patrons—most of them members of a political party advocating Syrian-Lebanese unity—drew their own firearms in response, we abandoned our table and sprinted back to our apartment. The next day, the regulars at the restaurant teased us for "overreacting"—and for leaving uneaten food on the table.

Such incidents demonstrate the power of the militias and other non-state actors, including Hezbollah, and the impotence of an army that does not ultimately secure the peace in Lebanon. Benedict acknowledged this dynamic in his call for an end to arms transfers between Lebanon and Syria. But his plea for shielding Lebanon from Syria's war has gone unheeded, as the recent explosion in Beirut illustrates. The attack had left over a hundred injured and killed eight, including the apparent target, a top security official who had exposed pro-Assad plots within the country. Lebanon could hardly be more vulnerable—divided into spheres of influence, its capital infiltrated by Syrians, Saudis, and Iranians who use the city-without-rules as an entrepôt for money, guns, and power.

My time in Lebanon revealed just how much turmoil lies beneath a veneer of social and psychological "recovery." People rarely speak of the civil war—as if, in building over many of the physical remains of the war, they have buried the memory, too, fixing instead on the vision put forth by advertisements for downtown construction sites: "the new Beirut... metropolitan, cosmopolitan, expensive." Since the civil war ended, the Beirut middle and upper classes have celebrated a newfound joie de vivre expressed in a lifestyle of fast cars, strong drinks, and beautiful women. Western visitors are bombarded with this lifestyle; the orientation at my university inBeirut did not advertise Lebanon's cultural achievements or geographical wonders, but rather its beach clubs and rooftop bars. Such fleeting pleasures, viewed as a response to the trauma of civil war, suggest that the process of psychological reconstruction is really a process of forgetting. That forgetting includes the abandonment of traditional Lebanese culture—a vibrant Mediterranean and Arab heritage—for the popular trends of the west and the borrowed wealth of the Persian Gulf. The elite Lebanese do not speak Arabic, but rather French or English, displaying pricy educations gained at the many prestigious international schools inBeirut.

Occasionally, when this social curtain fell back, my Lebanese friends and their families issued more candid views of the current state of their country. Older Christians tended to accuse the Muslims in power with having devastated Lebanon's environment in their haste to rebuild after the war. Among these Christians one detects an unmistakable disdain for the Muslims' allegedly uncouth manner and benighted tastes—an attitude stemming from the Christians' historical position as custodians of the French colonial legacy following independence in 1943. Meanwhile, Lebanese of every creed decry Israel's occupation of the West Bank and Gaza—even as they themselves discriminate against and disenfranchise the Palestinian refugees living in squalor in Beirut. Many still blame Yassir Arafat and his fedayeen militants for destabilizing Lebanon in the 1970s and exacerbating civil discord.

Such grudges evidently run deep in Lebanon, and yet despite fears about the Syrian conflict spilling over, the country has not regressed into civil war. You get the sense right now that peace precariously depends on carefully maintained fantasies. The strategic importance of Beirut, the spoils ofBeirut, are simply too valuable for war to happen again: if people say it often enough, then hopefully it will be so. But the artifice is beginning to come apart. If Syria's civil war spreads across the border, it will likely have ominous consequences. The risk in Lebanon is real, and the stakes are high.