BEIRUT, Lebanon — Near sunset, squads of young men gather along the narrow roads that lead in and out of their working-class Shiite neighborhood.
They block off the streets with metal barricades. Some arrive on scooters, wielding walkie-talkies, a sign of privilege in an area where many people struggle to buy food or pay a phone bill.
They have come for the anti-government protests that have been taking place nearby almost nightly since an explosion at Beirut’s port last week ravaged the city. The protesters want to tear down Lebanon’s sectarian political system, which they blame for incompetence, corruption and now for negligence that led to the blast, which killed at least 171 people and wounded thousands.
But these young men see the protests as a threat that could take power and privilege away from their Shiite sect and in particular from Hezbollah, the militant Shiite party, militia and Lebanon’s most powerful faction. They set up barricades not to support the protest but to make sure the angry crowds don’t come too close to their neighborhood.
“We have to protect ourselves,” said Ibrahim Abu Muhammad, the one member of the group who agreed to speak to a journalist. “Disparaging the leaders of the Shiite sect is a red line.”
Mr. Abu Muhammad, a devoted supporter of Hezbollah, pointed to a picture on his phone. It showed gallows erected by the protesters the night before, hanging cardboard cutouts of Hassan Nasrallah, secretary-general of Hezbollah, and Nabih Berri, the speaker of Parliament and leader of the allied Amal party.
“They hung the nooses for the Shiites,” he said, “only the Shiites.”
That was not true. A third noose, not visible in the picture on his phone, held a cutout of President Michel Aoun, a Christian, next to the two Shiite leaders.
That scene, in a nutshell, describes Lebanon’s problem.
Most Lebanese agree that the sectarian system of government, in which 18 religious sects divvy up power, profits and patronage, is the root of the country’s dysfunction and corruption. Many believe it should be replaced.
But no sect wants to give up its piece of the pie. That maxim perhaps goes double for the Shiite parties, who represent the largest sect and control the biggest share of the current system. Hezbollah has been one of the strongest forces opposing anti-government protests, which began last fall over the economic crisis and were revitalized by the explosion, both of which, protesters contend, are the result of a failed government.
The photo on Mr. Abu Muhammad’s phone, which had been circulating on his WhatsApp groups, shows that each sect also has its own sources of information, reinforcing each group’s insularity and propaganda.
The central Beirut neighborhood of Khandaq el-Ghamiq, where the young men were gathering, feels small and contained. Scooters are the preferred mode of transportation on its jammed main streets. In a pungent display of government dysfunction, garbage is piled on the streets here as it is in the rest of the city.
Most women dress modestly and cover their hair but walk freely. At night, men hang out on stoops and street corners, a reprieve from the hot, airless apartments they often share with extended family members.
Portraits of Mr. Nasrallah are everywhere. Large ones on billboards, smaller ones on walls and store fronts. Other leaders who show up next to him are Mr. Berri of the Amal party and Maj. Gen. Qassim Suleimani, the powerful Iranian commander who was killed in a United States airstrike in Iraq in January, and who is a reminder of Iran’s support for Hezbollah.
The neighborhood is about a mile from the port, where the explosion took place. The shock wave from the blast smashed windows, cracked walls and injured more than 70 people in the neighborhood.
People here are as angry at the government as anyone else but they fear that joining the protests would offend the leaders of Hezbollah and Amal. And for many, an attack on Hezbollah is an attack on them.
Muhammad Ali Jounie, who had stepped outside of the small grocery store where he works, seemed conflicted. At first, he seemed upset about the explosion and interested in a new government.
Then he said, “No matter what happens, I will side with my sect.”
Pressed on the seeming contradiction, he acknowledged the dueling impulses.
“I’m not convinced of what I’m saying,” he said, “but it’s what I’ll do. Lebanon is the country of sects. Put me in another country and I’ll be a different citizen.”
Mr. Jounie was not stretching the truth.
The unwieldy power-sharing system adopted after Lebanon’s civil war requires the president to be a Maronite Christian, the prime minister a Sunni Muslim and the speaker of Parliament a Shiite Muslim.
Sectarian quotas work their way down the chain and have concentrated power in the hands of a few leaders who survive by promoting the narrow interests of their sect and trusted allies. Corruption festers. There is little to no accountability.
And the state is so weak that people inevitably fall back on the safety provided by the sectarian party that runs their streets, making it nearly impossible to cultivate a sense of national identity. Hezbollah provides its supporters with jobs, social services and protection and demands loyalty in return.
“I can’t say anything to support the protests because I have a government job and a big part of the government is controlled by Hezbollah,” said one woman, who refused to be identified for fear of retribution.
Distraught over Lebanon’s economic tailspin, which eviscerated the value of her salary from $1,000 last year to about $200 this year, she initially joined the protests. But then she felt threatened, and stopped.
“If I join the protests,” she said, “I’ll be bullied and accused of treason.”
On Monday night the mood was tense. The government had just resigned, protesters were clashing with security forces, and the young Shiite squads were on high alert, monitoring the streets from the edge of the neighborhood.
Muhammad Khreiss, a local elder, floated in and out of a small store, which he used as an office.
“We’re headed towards federalism,” he said, railing against the resignation and the uncertain future that the country now faces. His wife, Zainab, sat at a desk, smoking a cigarette. Their 31-year-old son, Hassanein, who was slouched and leaning back in a chair, jumped in.
“I grew up with Hezbollah, its wars, its victories, its money,” he said. “Who else can give me that sense of confidence?”
Historically, Lebanon’s Shiites were disenfranchised and neglected by the state. Hezbollah helped draft a new chapter. It built a vast network of social services, including hospitals, schools and youth programs, that have lifted the community and garnered support and loyalty.
It also fought Israel and drove it out of southern Lebanon in 2000, a point of pride that stands in sharp contrast to the wars Arab states had launched and lost against Israel.
Thanks to Hezbollah, which the United States and other countries consider a terrorist organization, the Shiite community got a seat at the table and became power brokers, a status that was unthinkable decades ago.
Shiites here remember that.
“How can I know that if they come for Hezbollah and its weapons, they won’t come for me?” said the younger Mr. Khreiss.