I spent last week with the Kurdish Peshmerga as they battled Islamic State. With a film crew, I traveled a long segment of the 600-mile front along which the Kurds of Iraq are taking on the decapitators.
And I tell you, those decapitators, the barbarians with the black flag who, for the time being, have carved out a quasi-state straddling Iraq and Syria, will be defeated. They will be defeated because although they are very adept terrorists they are not good soldiers.
They will be defeated because they act tough for the camera while slitting the throats of defenseless hostages, but they scattered like rabbits when, on Aug. 26 around Albu Najem, a Kurdish people’s army moved in and reoccupied 77 square miles.
They will be defeated because, on that same day in the village of Tal Bassal, local journalists and observers recorded them being routed after inflicting a relatively small number of casualties among the Peshmerga (11, to my knowledge), mostly by planting explosives in the houses and mosques that they abandoned, in jerrycans, or under roadside rocks.
They will be defeated because, contrary to what one hears constantly repeated, they are not as brave as they seem: They love death less than the Kurds love life.
They will be defeated because fewer of them than many think are able to say convincingly why they fight, whereas the Kurds are defending their land and an idea, the dream of a country of their own and a model of society that is unique in the region.
They will be defeated because they are facing an increasingly professional army composed, exceptionally, of men and women of all ages and circumstances, many of whom left behind successful civilian lives, an army whose infantry comprises foot soldiers age 20, 30, 50 and older. I even encountered, in oven-like heat on the highest outcropping of Mount Zartak, an octogenarian serving shoulder to shoulder with his younger comrades. He had been keeping watch the night before, when an Islamic State column crept up the slope hoping to take the Kurdish encampment from behind.
They will be defeated because their leaders lie low and send their brainless zealots to the slaughter, whereas the Kurdish generals whom I have met are right there on the front line, respectable and respected: concrete bunkers for the troops but, for Maj. Gen. Maghdid Harki, the position most exposed to snipers firing from the village of Bartila.
They will be defeated because the black flags that can be seen through binoculars a few hundred yards away in the Kirkuk sector are planted in areas full of civilians—and one never wins by making civilians into human shields.
They will be defeated because the destroyed granaries, the blown-up agricultural facilities, the ruined roads, the collapsed bridge over an irrigation canal overgrown with reeds, the smoldering ruins—in short, the scenes of desolation in the zones that they have briefly controlled and been forced to abandon by the army of liberation—attest that they know no other policy than that of scorched earth. And with that policy one does not prevail for long.
They will be defeated because the Kurds, while loving life, are also capable, when necessary, of risking death to perform deeds of startling bravery, as suggested by the meaning of Peshmerga: one who confronts death. That is the story of one Jamal Mohammed Salih, who, seeing a suicide truck hurtling toward his position, reflected only a split second before putting his tank in its path to save his 80 comrades. He survived. He was gravely wounded, but he survived, and we were able to record his moving account.
They will be defeated because Islamic State has traitors in its ranks who inform the Peshmerga of its movements, allowing the Kurdish fighters to surprise the enemy.
They will be defeated because when, near Gwair, we fell on their radio frequency, it was not hard to imagine that, like the Khmer Rouge, they will end up killing each other in confusion.
They will be defeated because in the past year the Peshmerga, having quickly overcome their surprise of a year ago, have hardened their positions around the Mosul Dam, carved out trails in the scree above Qaraqosh, built a fort at the most strategically located site in the Kirkuk sector, fortified the rocky outcroppings in the Zartak zone, and, on the plains, dug trenches up to 10 yards wide to stop kamikaze trucks.
Finally, they will be defeated because a strong international coalition, led by the United States, is fighting alongside the Kurds. I visited its command center at an old air base from which Saddam Hussein’s chemical-weapons attacks were carried out. And I am convinced that the coalition will end up delivering the final blow to Islamic State.
Mr. Lévy’s books include “Left in Dark Times: A Stand Against the New Barbarism” (Random House, 2008). This op-ed was translated from the French by Steven B. Kennedy.