The quest for the caliphate will endure—with or without ISIS. Illustration by Brian Stauffer

Last May, Abu Mohammad al-Adnani, the second most powerful leader in the Islamic State, hinted that the caliphate was crumbling. “Whoever thinks that we fight to protect some land or some authority, or that victory is measured thereby, has strayed far from the truth,” he said, in a long audio message that was released to fellow-jihadis. He also suggested a shift in strategy. “It is the same—whether Allah blesses us with consolidation or we move into the bare, open desert, displaced and pursued.”

Adnani, a thirty-nine-year-old Syrian, ran the organization’s propaganda shop and a secret foreign-operations unit that recruited, trained, and assigned élite forces to the toughest missions. He orchestrated the terror attacks at the Bataclan theatre, in Paris, last year, and at the Brussels airport, in March. By this summer, though, he was on the run, hiding for months in an apartment building with hundreds of civilians in Raqqa, a city in northern Syria that dates to antiquity and serves as the Islamic State’s capital. The United States had picked up his trail, but had to use “tactical patience,” a senior Pentagon official told me, to avoid heavy collateral damage. “He just didn’t budge,” a senior U.S. official added. “We waited.”

Adnani finally emerged in August, after Syrian rebels drove the Islamic State out of Manbij, a small city that was a hub for its foreign fighters and a supply route to Turkey. The battle was decisive, costing the organization at least two thousand of its best fighters, including combat-hardened Chechens. In late August, Adnani left the apartment and sped west in an unmarked sedan to rally his forces in al-Bab, the city closest to Manbij. A U.S. drone picked him off with a laser-guided munition.

Since the Vietnam War, the U.S. military has shied away from body counts as a barometer of success, but Lieutenant General Sean MacFarland, the commander of the U.S.-led coalition in Iraq, estimated in August that forty-five thousand fighters had been “taken off the battlefield” in the Islamic State. Although that count may be high, other U.S. officials told me, the Islamic State’s losses have been staggering. It has surrendered fifty-seven per cent of its territory in Iraq and twenty-seven per cent in Syria—more than forty per cent of its total caliphate.

The Islamic State is now fighting to hang on to its two most valuable properties. On October 17th, Iraqi forces launched the long-awaited offensive to liberate Mosul, the largest city under Islamic State control, with two million residents. On November 6th, rebels in the Syrian Democratic Forces launched Euphrates Rage, an operation to free Raqqa, a city of some two hundred thousand. American airpower is backing both campaigns with daily bombing raids. Hundreds of additional fighters have been killed. The Islamic State’s de-facto news agency, Amaq, boasted that in the first six weeks of the Mosul battle a hundred and fifty-seven suicide bombers leaped into explosive-laden cars and drove straight into oncoming Iraqi troops. It posted an infographic showing the types of vehicles used in the attack.

The Islamic State’s emir, Abu Bakr al-Baghdadi, first announced the creation of the caliphate in June, 2014, from the pulpit of Mosul’s Grand Mosque. It was based on a utopian vision, dating back to Islam’s founding, that was modernized by the Muslim Brotherhood a century ago, hijacked and militarized by radical ideologues, and globalized by Al Qaeda. The Islamic State rejuvenated the jihad after the United States forced Al Qaeda in Iraq underground, in 2007, and killed Osama bin Laden, in 2011. It blitzed across Syria and Iraq, and then recruited tens of thousands of Muslims, from five continents, to govern and protect the new caliphate.

As a physical entity, the Islamic State’s conceit was probably never sustainable, at least at the pace and scope it attempted. Within eighteen months, it began to lose territory. Nevertheless, the quest for a modern caliphate continues. The brand is entrenched.

In Adnani’s final audio message, he described a fallback plan, which was reflected in the Islamic State’s media this fall. Its slickest publication had been Dabiq, a magazine named for a Syrian town where, in the seventh century, Armageddon was prophesied to play out in an apocalyptic battle with infidel forces from the Roman Empire. Symbolically, the village was a potent recruiting tool, even though Dabiq today is of no strategic value, with only three thousand residents. It fell, in October, to the militia now advancing on Raqqa. The organization renamed its magazine Rumiyah, or Rome—an allusion to the prophecies foretelling the fall of the West and a signal that the Islamic State operations may increasingly shift from inside the caliphate to outside.

An article in the November issue, accompanied by a photograph of the Macy’s Thanksgiving Day Parade, urged jihadis to attack outdoor festivals, markets, political rallies, and pedestrian-clogged streets: “The method of such an attack is that a vehicle is plunged at a high speed into a large congregation of kuffar”—non-believers—“smashing their bodies with the vehicle’s strong outer frame while advancing forward—crushing their heads, torsos, and limbs under the vehicle’s wheels and chassis.” The article provided a list of vehicles best suited to killing. Next to a picture of a U-Haul, it said that the ideal truck is “double-wheeled, giving victims less of a chance to escape being crushed by the vehicle’s tires.”

In his message, Adnani appealed to the faithful to launch lone-wolf attacks. “Determination! Determination!” he urged. “The smallest act you do in their lands is more beloved to us than the biggest act done here.”

On November 21st, the State Department issued an international travel alert, warning all Americans that “credible information” indicated “the heightened risk of terrorist attacks throughout Europe.” The alert will be in effect for the next three months. Four days later, France announced the arrest of five Islamic State operatives who were planning an attack for December 1st. The targets reportedly included the Champs-Élysées and the Disneyland park outside Paris.

Adnani also envisioned an inhiyaz ila al-sahraa, a retreat into the desert. The term was meant in the strategic sense of regrouping in order to return to the battle. There is a precedent. After the U.S. troop surge in 2007, the jihadis slipped away into the remote plains, villages, farmlands, and, particularly, the vulnerable “seams” along the borders of Iraq, Syria, Lebanon, Jordan, and Turkey. The movement rebuilt, recruited, broke into prisons to bolster its ranks, and prepared for the surprise sweep into Syria and Iraq seven years later.

“O America,” Adnani said. “Would we be defeated and you be victorious if you were to take Mosul or Sirte or Raqqa? . . . Certainly not! We would be defeated and you victorious only if you were able to remove the Koran from Muslims’ hearts.”

On a balmy autumn day, I drove through Lebanon’s Bekaa Valley toward a front line with the Islamic State. The valley is Wild West territory, ruled by armed clans largely unchallenged by the government. For miles and miles, farmers were harvesting the willowy, thin-leafed stalks that make hashish, a mainstay of the local economy. From the valley, I headed north, on narrow, winding roads, to the Qalamoun Mountains, a voluptuous but rugged range near the Syrian border, known for its apricot trees and chalky limestone quarries. It is now a hub for more than a thousand militants—some locals claim the number is at least twice that—who have burrowed into the brown hills, bringing with them the wars in Syria and Iraq.