In the desert swelter of southern Pakistan, the scent of rose­water mixed with a waft of hashish smoke. Drummers pounded away as celebrants swathed in red pushed a camel bedecked with garlands, tinsel and multihued scarfs through the heaving crowd. A man skirted past, grinning and dancing, his face glistening like the golden dome of a shrine nearby. "Mast Qalandar!" he cried. "The ecstasy of Qalandar!"

The camel reached a courtyard packed with hundreds of men jumping in place with their hands in the air, chanting "Qalandar!" for the saint buried inside the shrine. The men threw rose petals at a dozen women who danced in what seemed like a mosh pit near the shrine's entrance. Enraptured, one woman placed her hands on her knees and threw her head back and forth; another bounced and jiggled as if she were astride a trotting horse. The drumming and dancing never stopped, not even for the call to prayer.

I stood at the edge of the courtyard and asked a young man named Abbas to explain this dancing, called dhamaal. Though dancing is central to the Islamic tradition known as Sufism, dhamaal is particular to some South Asian Sufis. "When a djinn infects a human body," Abbas said, referring to one of the spirits that populate Islamic belief (and known in the West as "genies"), "the only way we can get rid of it is by coming here to do dhamaal." A woman stumbled toward us with her eyes closed and passed out at our feet. Abbas didn't seem to notice, so I pretended not to either.

"What goes through your head when you are doing dhamaal?" I asked.

"Nothing. I don't think," he said. A few women rushed in our direction, emptied a water bottle on the semiconscious woman's face and slapped her cheeks. She shot upright and danced back into the crowd. Abbas smiled. "During dhamaal, I just feel the blessings of Lal Shahbaz Qalandar wash over me."

Every year, a few hundred thousand Sufis converge in Seh- wan, a town in Pakistan's southeastern Sindh province, for a three-day festival marking the death of Lal Shahbaz Qalandar, in 1274. Qalandar, as he is almost universally called, belonged to a cast of mystics who consolidated Islam's hold on this region; today, Pakistan's two most populous provinces, Sindh and Punjab, comprise a dense archipelago of shrines devoted to these men. Sufis travel from one shrine to another for festivals known as urs, an Arabic word for "marriage," symbolizing the union between Sufis and the divine.

Sufism is not a sect, like Shiism or Sunnism, but rather the mystical side of Islam—a personal, experiential approach to Allah, which contrasts with the prescriptive, doctrinal approach of fundamentalists like the Taliban. It exists throughout the Muslim world (perhaps most visibly in Turkey, where whirling dervishes represent a strain of Sufism), and its millions of followers generally embrace Islam as a religious experience, not a social or political one. Sufis represent the strongest indigenous force against Islamic fundamentalism. Yet Western countries have tended to underestimate their importance even as the West has spent, since 2001, millions of dollars on interfaith dialogues, public diplomacy campaigns and other initiatives to counter extremism. Sufis are particularly significant in Pakistan, where Taliban-inspired gangs threaten the prevailing social, political and religious order.

Pakistan, carved out of India in 1947, was the first modern nation founded on the basis of religious identity. Questions about that identity have provoked dissent and violence ever since. Was Pakistan to be a state for Muslims, governed by civilian institutions and secular laws? Or an Islamic state, governed by clerics according to sharia, or Islamic law? Sufis, with their ecumenical beliefs, typically favor the former, while the Taliban, in their fight to establish an extreme orthodoxy, seek the latter. The Taliban have antiaircraft weapons, rocket-propelled grenades and squads of suicide bombers. But the Sufis have drums. And history.

I asked Carl Ernst, an author of several books about Sufism and a professor of Islamic studies at the University of North Carolina at Chapel Hill, whether he thought Pakistan's Sufis could survive the wave of militant Islam sweeping east from the region along the Afghanistan border. "Sufism has been a part of the fabric of life in the Pakistan region for centuries, while the Taliban are a very recent phenomenon without much depth," he replied in an e-mail. "I would bet on the Sufis in the long run." This summer, the Taliban attracted a few hundred people to witness beheadings in Pakistan's tribal areas. In August, more than 300,000 Sufis showed up to honor Lal Shahbaz Qalandar.

Qalandar was an ascetic; he dressed in rags and tied a rock around his neck so that he was constantly bowing before Allah. His given name was Usman Marwandi; "Qalandar" was used by his followers as an honorific indicating his superior standing in the hierarchy of saints. He moved from a suburb of Tabriz, in modern-day Iran, to Sindh in the early 13th century. The remainder of his biography remains murky. The meaning of lal, or "red," in his name? Some say he had auburn hair, others believe he wore a red robe and still others say he once was scalded while meditating over a pot of boiling water.

In migrating to Sindh, Qalandar joined other mystics fleeing Central Asia as the Mongols advanced. Many of them settled temporarily in Multan, a city in central Punjab that came to be known as the "city of saints." Arab armies had conquered Sindh in 711, a hundred years after the founding of Islam, but they had paid more attention to empire-building than to religious conversions. Qalandar teamed with three other itinerant preachers to promote Islam amid a population of Muslims, Buddhists and Hindus.

The "four friends," as they became known, taught Sufism. They eschewed fire-and-brimstone sermons, and rather than forcibly convert those belonging to other religions, they often incorporated local traditions into their own practices. "The Sufis did not preach Islam like the mullah preaches it today," says Hamid Akhund, a former secretary of tourism and culture in the Sindh government. Qalandar "played the role of integrator," says Ghulam Rabbani Agro, a Sindhi historian who has written a book about Qalandar. "He wanted to take the sting out of religion."

Gradually, as the "friends" and other saints died, their enshrined tombs attracted legions of followers. Sufis believed that their descendants, referred to as pirs, or "spiritual guides," inherited some of the saints' charisma and special access to Allah. Orthodox clerics, or mullahs, considered such beliefs heretical, a denial of Islam's basic creed: "There is no God but God, and Muhammad is his Prophet." While pirs encouraged their followers to engage Allah in a mystical sense and relish the beauty of the Koran's poetic aspects, the mullahs typically instructed their followers to memorize the Koran and study accounts of the Prophet's life, known collectively as the Hadith.

While the tension between Sufis and other Muslims continued through history, in Pakistan the dynamic between the two groups has lately entered an especially intense phase with the proliferation of militant groups. In one example three years ago, terrorists attacked an urs in Islamabad, killing more than two dozen people. After October 2007, when former Prime Minister Benazir Bhutto—a native of Sindh province with roots in Sufism—returned from exile, terrorists twice targeted her for assassination, succeeding that December. Meanwhile, the Taliban persisted in their terror campaign against the Pakistani military and launched attacks in major cities.

I had seen the extremists up close; in the fall of 2007 I traveled throughout northwestern Pakistan for three months, reporting a story on the emergence of a new, considerably more dangerous generation of Taliban. In January 2008, two days after that story was published in the New York Times Magazine, I was expelled from Pakistan for traveling without government authorization to areas where the Taliban held sway. The next month, Bhutto's political party swept to victory in national elections, heralding the twilight of President Pervez Musharraf's military rule. It was an odd parallel: the return of democracy and the rise of the Taliban. In August, I secured another visa from the Pakistani government and went back to see how the Sufis were faring.

Over dinner in a Karachi hotel, Rohail Hyatt told me that the "modern-day mullah" was an "urban myth" and that such authoritarian clerics have "always been at war with Sufis." Hyatt, a Sufi, is also one of Pakistan's pop icons. Vital Signs, which he founded in 1986, became the country's biggest rock band in the late '80s. In 2002, the BBC named the band's 1987 hit, "Dil, Dil Pakistan" ("Heart, Heart Pakistan"), the third most popular international song of all time. But Vital Signs became inactive in 1997, and lead singer Junaid Jamshed, Hyatt's longtime friend, became a fundamentalist and decided that such music was un-Islamic.

Hyatt watched with despair as his friend adopted the rituals, doctrine and uncompromising approach espoused by the urban mullahs, who, in Hyatt's view, "believe that our identity is set by the Prophet" and less by Allah, and thus mistakenly gauge a man's commitment to Islam by such outward signs as the length of his beard, the cut of his trousers (the Prophet wore his above the ankle, for comfort in the desert) and the size of the bruise on his forehead (from regular, intense prayer). "These mullahs play to people's fears," Hyatt said. " ‘Here is heaven, here is hell. I can get you into heaven. Just do as I say.' "

I hadn't been able to find a clear, succinct definition of Sufism anywhere, so I asked Hyatt for one. "I can explain to you what love is until I turn blue in the face. I can take two weeks to explain everything to you," he said. "But there is no way I can make you feel it until you feel it. Sufism initiates that emotion in you. And through that process, religious experience becomes totally different: pure and absolutely nonviolent."

Hyatt is now the music director for Coca-Cola in Pakistan, and he hopes he can leverage some of his cultural influence—and access to corporate cash—to convey Sufism's message of moderation and inclusiveness to urban audiences. (He used to work for Pepsi, he said, but Coke is "way more Sufic.") He recently produced a series of live studio performances that paired rock acts with traditional singers of qawwali, devotional Sufi music from South Asia. One of the best-known qawwali songs is titled "Dama Dum Mast Qalandar," or "Every Breath for the Ecstasy of Qalandar."

Several politicians have also tried to popularize Sufism, with varying degrees of success. In 2006, as Musharraf faced political and military challenges from the resurgent Taliban, he established a National Sufi Council to promote Sufi poetry and music. "The Sufis always worked for the promotion of love and oneness of humanity, not for disunity or hatred," he said at the time. But Musharraf's venture was perceived as less than sincere.

"The generals hoped that since Sufism and devotion to shrines is a common factor of rural life, they would exploit it," Hamid Akhund told me. "They couldn't." Akhund chuckled at the thought of a centralized, military government trying to harness a decentralized phenomenon like Sufism. The Sufi Council is no longer active.

The Bhuttos—most prominently, Benazir and her father, Zulfikar Ali Bhutto—were much better at marshaling Sufi support, not least because their hometown lies in Sindh province and they have considered Lal Shahbaz Qalandar their patron saint. Qalandar's resting place became, in the judgment of University of Amsterdam scholar Oskar Verkaaik, "the geographical center of [the elder] Bhutto's political spirituality." After founding the Pakistan Peoples Party, Bhutto was elected president in 1971 and prime minister in 1973. (He was ousted in a coup in 1977 and hanged two years later.)

As Benazir Bhutto began her first campaign for prime minister, in the mid-1980s, her followers would greet her with the chant, "Benazir Bhutto Mast Qalandar" ("Benazir Bhutto, the ecstasy of Qalandar"). In late 2007, when she returned to Pakistan from an exile imposed by Musharraf, she received a heroine's welcome, especially in Sindh.

In Jamshoro, a town almost three hours north of Karachi, I met a Sindhi poet named Anwar Sagar. His office had been torched during the riots that followed Benazir Bhutto's assassination. More than six months later, smashed windowpanes were still unrepaired and soot covered the walls. "All the Bhuttos possess the spirit of Qalandar," Sagar told me. "The message of Qalandar was the belief in love and God." From his briefcase he pulled out a poem he had written just after Bhutto was killed. He translated the final lines:
She rose above the Himalayas,
Immortal she became,
The devotee of Qalandar became Qalandar herself.

"So who is next in line?" I asked. "Are all Bhuttos destined to inherit Qalandar's spirit?"

"This is just the beginning for Asif," Sagar said, referring to Asif Ali Zardari, Benazir Bhutto's widower, who was elected president of Pakistan this past September. "So he hasn't attained the level of Qalandar yet. But I have great hope in Bilawal"—Bhutto and Zardari's 20-year-old son, who has been selected to lead the Pakistan Peoples Party after he finishes his studies at Oxford University in England—"that he can become another Qalandar."

Musharraf, a general who had seized power in a 1999 coup, resigned from office a week into my most recent trip. He had spent the better part of his eight-year regime as president, military chief and overseer of a compliant parliament. Pakistan's transition from a military government to a civilian one involved chipping away at his almost absolute control over all three institutions one by one. But civilian leadership by itself was no balm for Pakistan's many ills; Zardari's new regime faces massive challenges regarding the economy, the Taliban and trying to bring the military intelligence agencies under some control.

In the seven months that I had been away, the economy had gone from bad to worse. The value of the rupee had fallen almost 25 percent against the dollar. An electricity shortage caused rolling blackouts for up to 12 hours a day. Reserves of foreign currencies plunged as the new government continued to subsidize basic amenities. All these factors contributed to popular discontent with the government, an emotion that the Taliban exploited by lambasting the regime's perceived deficiencies. In Karachi, the local political party covered the walls of buildings along busy streets with posters that read: "Save Your City From Talibanization."

Perhaps the biggest challenge for the new government is reining in the military's intelligence agencies, particularly the Inter-Services Intelligence, or ISI. The Pakistan Peoples Party has long been considered an anti-establishment party, at odds with the agencies. In late July, the PPP-led government announced that it was placing the ISI under the command of the Interior Ministry, wresting it from the army—then days later, under pressure from the military, reversed itself. A uniformed president may symbolize a military dictatorship, but Pakistan's military intelligence agencies, ISI and Military Intelligence (MI), are the true arbiters of power.

In August, I got what I believe was a firsthand indication of the extent of their reach. Two days after Musharraf bid farewell, I began my trip to Sehwan for the urs for Qalandar, along with photographer Aaron Huey; his wife, Kristin; and a translator whom it is best not to name. We had barely left Karachi's city limits when my translator took a phone call from someone claiming to work at the Interior Ministry Secretariat in Karachi. The caller peppered him with questions about me. The translator, sensing something odd, hung up and called the office of a senior bureaucrat in the Interior Ministry. A secretary answered the phone and, when we shared the name and title our caller had given, confirmed what we already suspected: "Neither that person nor that office exists." The secretary added: "It's probably just the [intelligence] agencies."

We continued north on the highway into the heart of Sindh, past water buffaloes soaking in muddy canals and camels resting in the shade of mango trees. About an hour later, my phone rang. The caller ID displayed the same number as the call that had supposedly come from the Interior Ministry Secretariat.
"Hello?"
"Nicholas?"
"Yes."
"I am a reporter from the Daily Express newspaper. I want to meet you to talk about the current political situation. When can we meet? Where are you? I can come right now."

"Can I call you back?" I said, and hung up.

My heart raced. Images of Daniel Pearl, the Wall Street Journal reporter who was kidnapped and beheaded by Islamic militants in Karachi in 2002, flashed through my mind. Pearl's last meeting had been with a terrorist pretending to be a fixer and translator. Many people believe that the Pakistani intelligence agencies were involved in Pearl's killing, as he was researching a possible link between the ISI and a jihadi leader with ties to Richard Reid, the so-called shoe bomber.

My phone rang again. An Associated Press reporter I knew told me that her sources in Karachi said the intelligence agencies were searching for me. I had assumed as much. But what did they want? And why would they request a meeting by pretending to be people who didn't exist?

The car fell silent. My translator made a few calls to senior politicians, bureaucrats and police officers in Sindh. They said they were treating the two phone calls as a kidnapping threat and would provide us with an armed escort for the rest of our trip. Within an hour, two police trucks arrived. In the lead truck, a man armed with a machine gun stood in the bed.

Another phone call, this time from a friend in Islamabad.
"Man, it's good to hear your voice," he said.
"Why?"
"Local TV stations are reporting that you've been kidnapped in Karachi."

Who was planting these stories? And why? With no shortage of conspiracy theories about fatal "car accidents" involving people in the bad graces of the intelligence agencies, I took the planted stories as serious warnings. But the urs beckoned. The four of us collectively decided that since we had traveled halfway around the world to see the shrine of Lal Shahbaz Qalandar, we would do our damndest to get there, even if under police protection. After all, we could use Qalandar's blessings.

That evening, as the setting sun burned the color of a Creamsicle as it lit the sugar-cane fields on the horizon, I turned to the translator, hoping to lighten the mood.

"It's really beautiful here," I said.

He nodded, but his eyes stayed glued to the road. "Unfortunately, the fear factor spoils the whole fun of it," he said.

By then we could see buses clogging the highway, red flags flapping in the wind as the drivers raced for Qalandar's shrine. The railway ministry had announced that 13 trains would be diverted from their normal routes to transport worshipers. Some devotees even pedaled bicycles, red flags sticking up from the handlebars. We roared down the road in the company of Kalashnikov-toting police, a caravan of armed pilgrims.

The campsites began appearing about five miles from the shrine. Our car eventually mired in a human bog, so we parked and continued on foot. The alleys leading to the shrine reminded me of a carnival fun house—an overwhelming frenzy of lights, music and aromas. I walked beside a man blowing a snake charmer's flute. Stores lined the alley, with merchants squatting behind piles of pistachios, almonds and rosewater-doused candies. Fluorescent lights glowed like light sabers, directing lost souls to Allah.

Groups of up to 40 people heading for the shrine's golden dome carried long banners imprinted with Koranic verses. We followed one group into a tent packed with dancers and drummers next to the shrine. A tall man with curly, greasy shoulder-length hair was beating on a keg-size drum hanging from a leather strap around his neck. The intensity in his eyes, illuminated by a single bulb that dangled above our heads, reminded me of the jungle cats that stalked their nighttime prey on the nature shows I used to watch on TV.

A man in white linen lunged flamboyantly into a clearing at the center of the crowd, tied an orange sash around his waist and began to dance. Soon he was gyrating and his limbs were trembling, but with such control that at one point it seemed that he was moving only his earlobes. Clouds of hashish smoke rolled through the tent, and the drumming injected the space with a thick, engrossing energy.

I stopped taking notes, closed my eyes and began nodding my head. As the drummer built toward a feverish peak, I drifted unconsciously closer to him. Before long, I found myself standing in the middle of the circle, dancing beside the man with the exuberant earlobes.

"Mast Qalandar!" someone called out. The voice came from right behind me, but it sounded distant. Anything but the drumbeat and the effervescence surging through my body seemed remote. From the corner of my eye, I noticed photographer Aaron Huey high-stepping his way into the circle. He passed his camera to Kristin. In moments, his head was swirling as he whipped his long hair around in circles.

"Mast Qalandar!" another voice screamed.

If only for a few minutes, it didn't matter whether I was a Christian, Muslim, Hindu or atheist. I had entered another realm. I couldn't deny the ecstasy of Qalandar. And in that moment, I understood why pilgrims braved great distances and the heat and the crowds just to come to the shrine. While spun into a trance, I even forgot about the danger, the phone calls, the reports of my disappearance and the police escort.

Later, one of the men who had been dancing in the circle approached me. He gave his name as Hamid and said he had traveled more than 500 miles by train from northern Punjab. He and a friend were traversing the country, hopping from one shrine to another, in search of the wildest festival. "Qalandar is the best," he said. I asked why.

"He could communicate directly with Allah," Hamid said. "And he performs miracles."

"Miracles?" I asked, with a wry smile, having reverted to my normal cynicism. "What kind of miracles?"

He laughed. "What kind of miracles?" he said. "Take a look around!" Sweat sprayed from his mustache. "Can't you see how many people have come to be with Lal Shahbaz Qalandar?"

I looked over both of my shoulders at the drumming, the dhamaal and the sea of red. I stared back at Hamid and tilted my head slightly to acknowledge his point.

"Mast Qalandar!" we said.

Nicholas Schmidle is a fellow at the New America Foundation in Washington, D.C. His book, To Live or To Perish Forever: Two Years Inside Pakistan, will be published May 2009 by Henry Holt.
Aaron Huey is based in Seattle. He has been photographing Sufi life in Pakistan since 2006.