There was a time in the Middle East when key chains, computer screens, posters and memorabilia showed the smiling face of Hassan Nasrallah, while excepts from his speeches blared out from cellphones.

From Lebanon to Mauritania, people dedicated songs to him, women promised undying love and supporters pledged to shed their last drop of blood for him.

After devotees credited Hezbollah with single-handedly ending the Israeli occupation of southern Lebanon in 2006, Mr. Nasrallah, the group’s leader, secured a place in history as a legendary Middle Eastern strongman.

“Since [Egypt’s] Gamal Abdel al-Nasser enchanted Arab youth in the 1960s, no political leader — and especially not a Shia — has captured as many hearts and minds of Arabs and Muslims,” wrote Tobias Thiel, an expert in Middle Eastern politics at the London School of Economics.

“He has become an Arab Che Guevara, who personifies an Islamist resistance struggle.”

But today Mr. Nasrallah is hunkered down in his Southern Beirut stronghold and even diehard supporters — mainly Lebanon’s Shiites — are starting to question his leadership.

The reason: his intervention in the Syrian civil war. In sending Hezbollah recruits to fight for President Bashar al-Assad, analysts believe Mr. Nasrallah is fuelling sectarian conflict and fanning the flames in an already turbulent region.

“A lot of people in Lebanon and around the region have been very critical of their involvement,” says Rami Khouri, a journalist and director of the Issam Fares Institute for Public Policy & International Affairs at the American University of Beirut.

“Some supporters are rumbling.”

“No one is attacking Lebanon,” says Aurel Braun, professor of government at Harvard University, currently a visiting professor at the University of Toronto.

“They say they are defending the country against Israel. But they are not defending anyone. This is a lie.”

Since the Syrian civil war broke out in 2011, the fortunes of Mr. Nasrallah and Hezbollah, which many countries, including Canada, consider a terrorist organization, have fallen sharply.

Hezbollah-controlled areas in Lebanon have been attacked by Sunni militants and Mr. Nasrallah’s posters no longer beam from the shattered walls of his stronghold in southern Beirut.

People in Lebanon and abroad are now arguing for the disarmament of the organization. “People think they should not remain as an armed group outside the control of the Lebanese government,” says Mr. Khouri.

If Mr. Assad, a member of the Alawite sect, an offshoot of Shiite Islam, lost power and Sunni rebels took over Syria, there are fears innocent Lebanese could end up suffering harsh consequences.

“The war in Syria could spill over in a larger scale to Lebanon,” says Mr. Braun.

The country is already feeling the results of Hezbollah’s involvement in Syria as extremist Sunni groups launched two attacks in south Beirut this year. “Hezbollah is much more vulnerable because of that. That has contributed to them looking weak. They looked almost invincible, but now they’ve had two major operations here that killed many people. Hezbollah doesn’t benefit from that kind of thing,” says Magnus Ranstorp, a Hezbollah expert and research director at the Swedish National Defence College.

The Syrian adventure is a rare miscalculation in a career that has taken Mr. Nasrallah, 53, to the pinnacle of the militant Shiite group.

The oldest of nine children from a poor family in Southern Lebanon, he attended top Shiite seminaries in Iran and Iraq before joining Amal, a resistance Shiite movement. But he found the group too tame and in 1982 moved to Hezbollah, an organization created by Iran to expand its 1979 Islamic Revolution and oppose Israeli occupation.

A decade l a t e r, he replaced Abbas al Musawi as the group’s secretary-general after Mr. Musawi was killed by an Israeli airstrike. Fear of suffering a similar fate has kept Mr. Nasrallah in hiding for nearly a decade, frequently on the move. Experts think he is now living in Beirut.

Meanwhile, his reputation snowballed. In 2004, the Hezbollah leader was credited with negotiating the release of hundreds of Palestinian and Lebanese prisoners from Israeli jails, but his popularity soared after his “divine victory” in the 2006 Israeli-Lebanese war.

A poll that year by the Ibn Khaldun Centre, an Egyptian non-governmental organization, saw Mr. Nasrallah come top as the most popular figure in the Middle East, while a Lebanese poll found Hezbollah supported by 89% of the country’s Sunnis, despite being a Shiite organization.

Mr. Nasrallah is the classic example of a charismatic leader, says Mr. Thiel. Followers are not allowed to question his actions, he is credited with supernatural qualities, and he demands absolute obedience and devotion.

“Newspaper reports, interviews and discussion groups surfacing after 2006 provide evidence that Nasrallah is perceived as beyond human,” Mr. Thiel wrote.

“A young, previously secular, Lebanese Shia woman, clearly places Nasrallah in the domain of the semi-divine, when she is quoted in the German weekly as saying, ‘Nasrallah’s not an ordinary person. He’s something from God to us.’” But Mr. Nasrallah is unique even by these standards, says Mr. Ranstorp. “He is incorruptible. He lives like he preaches. He is different from most political leaders in the Middle East in that sense.”

“Most Islamic leaders would talk about sending people to sacrifice themselves, but rarely do they send their own sons,” he adds. “And in 1997, Hadi Nasrallah died in the battlefield in Southern Lebanon.”

In addition to launching and fighting attacks from Israel, Mr. Nasrallah understood the importance of infiltrating the Lebanese political establishment. Under his direction, Hezbollah set up a political party and today it has about a dozen seats in Parliament.

That’s enough power in the fractured assembly to influence policy and even secure the dismissal of government ministers it does not agree with.

“They are a state within a state. They are not democratic,” says Prof. Braun.

“They bully people. If you disobey, they punish you. They are like the drug cartels in Colombia, or like the fascists in Italy.”

Despite such seeming autonomy, observers say Iran remains the power behind the throne, with Ali Khamenei, Iran’s Supreme Spiritual Leader, directing most of the group’s international activities.

“They will do what Iran tells them to do,” says Mr. Ranstorp who was the first scholar to establish the links among Iran, Syria and Hezbollah.

“They will not act independently, they will act in consultation. Terrorism is a very small, concealed part of Hezbollah. It’s released only in very special occasions. It’s really an Iranian intelligence operation with the Iranian Revolutionary Guards Corps.”

Analysts say one of the main reasons for Hezbollah’s Syrian involvement is its need to use the country as a pipeline. Iran and Syria provide the largest chunk of funds and weapons to the organization. But Mr. Ranstorp thinks getting dragged into the Syrian conflict was a huge miscalculation.

“He’s lost the halo. All the good image that Nasrallah had from the 2006 war is dissipated. Today Sunnis hate him.”

Even if Mr. Assad wins the war — securing Hezbollah’s survival — Mr. Nasrallah will be hard pressed to regain his lost popularity.

“It will probably take a conflict and probably against an external enemy like Israel for it to be affected,” Mr. Ranstorp says.

“But the big thing for Nasrallah is that the pipeline would survive between Iran and Syria into Hezbollah. And that is more important to him than his own popularity.”