By George Packer/ The New Yorker

A humanitarian crisis that could turn into a genocide is taking place right now in the mountains of northwestern Iraq. It hasn’t made the front page, because the place and the people are obscure, and there’s a lot of other horrible news to compete with. I’ve learned about it mainly because the crisis has upended the life of someone I wrote about in the magazine several weeks ago.

Last Sunday, Karim woke up around 7:30 A.M., after coming home late the night before. He was about to have breakfast when his phone rang—a friend was calling to see how he was doing. Karim is a Yazidi, a member of an ancient religious minority in Iraq. Ethnically, he’s Kurdish. An engineer and a father of three young children, Karim spent years working for the U.S. Army in his area, then for an American medical charity. He’s been waiting for months to find out whether the U.S. government will grant him a Special Immigrant Visa because of his service, and because of the danger he currently faces.

Karim is from a small town north of the district center, Sinjar, between Mosul and the Syrian border. Sinjar is a historic Yazidi area with an Arab minority. Depending on who’s drawing the map, Sinjar belongs to either the northernmost part of Iraq or the westernmost part of Kurdistan. Since June, when extremist fighters from the Islamic State in Iraq and al-Sham captured Mosul, they’ve been on the outskirts of Sinjar, facing off against a small number of Kurdish peshmerga militiamen. ISIS regards Yazidis as devil worshippers, and its fighters have been executing Yazidi men who won’t convert to Islam on the spot, taking away the women as jihadi brides. So there were many reasons why a friend might worry about Karim.

“I don’t know,” Karim said. “My situation is O.K.” “No, it’s not O.K.!” his friend said. “Sinjar is under the control of ISIS.”

Karim had not yet heard this calamitous news. “I’ll call some friends and get back to you,” he said.

But the cell network was jammed, so Karim walked to his father’s house. His father told him that thousands of people from Sinjar were headed their way, fleeing north through the mountains to get out of Iraq and into Kurdistan. It suddenly became clear that Karim would have to abandon his home and escape with his family.

ISIS had launched its attack on Sinjar during the night. Peshmerga militiamen were outgunned—their assault rifles against the extremists’ captured fifty-caliber guns, rocket-propelled grenades, mortars, anti-aircraft weapons, and armored vehicles. The Kurds began to run out of ammunition, and those who could retreated north toward Kurdistan. By dawn, the extremists were pouring into town. Later, ISIS posted triumphant photos on Twitter: bullet-riddled corpses of peshmerga in the streets and dirt fields; an ISIS fighter aiming his pistol at the heads of five men lying face down on the ground; Arab locals who stayed in Sinjar jubilantly greeting the new occupiers.

Karim had time to do just one thing: burn all the documents that connected him to America—photos of him posing with Army officers, a CD from the medical charity—in case he was stopped on the road by militants or his house was searched. He watched the record of his experience during the period of the Americans in Iraq turn to ash, and felt nothing except the urge to get to safety.

By 9:30 A.M., Karim and his extended family were crowded into his brother’s car and his father’s pickup truck. They’d had no time to pack, and for the drive through the heat of the desert they took nothing but water, bread, canned milk for Karim’s two-year-old son, and their AK-47s. At first, Karim’s father refused to go along. A stubborn man, he said, “Let them kill me in my town, but I will never leave it.” Fortunately, the father’s paralyzed cousin, who had been left behind by his family, pleaded with him, and at the last minute the two old men joined the exodus. Karim’s twenty or so family members were the last to get out of the area by car, and they joined a massive traffic jam headed northwest. Thousands of other Yazidi families had to flee on foot into the mountains: “They couldn’t leave. They didn’t know how to leave. They waited too long to leave,” Karim said.

Karim drove in a convoy of two hundred and fifty or three hundred cars. They stuck together for safety. The group decided against taking the most direct route to Kurdistan, which would have taken them through the Arab border town of Rabiya. ISIS wasn’t the only danger—Yazidi Kurds have come to regard Sunni Arabs generally as a threat. So they drove across the border at an unmarked point into Syria, where Kurdish rebels—who form one side in the complex Syrian civil war—were in control of the area. The rebels waved the convoy on, while Syrian Arab villagers stared or took videos with their mobile phones. A relative of Karim’s happened to be a cigarette smuggler and knew the way across the desert once the roads disappeared. (“Everyone and everything has his day,” Karim told me.) The undercarriage of Karim’s car began to break off in pieces. They drove for hours through Syria, crossed back into Iraq, and shortly afterward reached a checkpoint into Kurdistan, where the line of cars was so long that they had to wait for hours more. It wasn’t until nightfall, nearly twelve hours after they had fled their home, that Karim and his family reached the Kurdish town of Dohuk, where he happened to have a brother who gave them shelter in his small apartment.

“Compared with other people here, I’m in heaven,” Karim said by phone from Dohuk. “Some are in camps for refugees. It’s very hot and very hard. We are safe, but thousands of families are in the mountains. Thousands.”

Karim heard that one young man had been executed by ISIS for no reason other than being Yazidi. A friend of Karim’s was hiding in the mountains, running low on supplies, and out of battery power in his phone. Another friend, an Arab (“He is not a religion guy, he’s open-minded, it doesn’t matter if you’re Christian or Yazidi,” Karim said), had stayed in Sinjar and was trapped in his home. Now ISIS was going house to house, with information provided by locals, looking for Iraqi soldiers and police, for people with money, for Kurds. They had already taken away the friend’s brother, a police officer. No one knows for sure how many people ISIS has killed since the attack on Sinjar. Karim heard that it is many hundreds.

Prince Tahseen Said, “the world leader of the Yazidis,” has issued an appeal to Kurdish, Iraqi, Arab, and European leaders, as well as to Ban Ki-moon and Barack Obama. It reads: “I ask for aid and to lend a hand and help the people of Sinjar areas and its affiliates and villages and complexes which are home to the people of the Yazidi religion. I invite [you] to assume [your] humanitarian and nationalistic responsibilities towards them and help them in their plight and the difficult conditions in which they live today.”

It’s hard to know what, if anything, is left of the humanitarian responsibilities of the international community. The age of intervention is over, killed in large part by the Iraq war. But justifiable skepticism about the use of military force seems also to have killed off the impulse to show solidarity with the helpless victims of atrocities in faraway places. There’s barely any public awareness of the unfolding disaster in northwestern Iraq, let alone a campaign of international support for the Yazidis—or for the Christians who have been driven out of Mosul or the Sunni Arabs who don’t want to live under the tyranny of ISIS. The front-page news continues to be the war in Gaza, a particular Western obsession whether one’s views are pro-Israel, pro-Palestinian, pro-peace, or pro-plague-on-both-houses. Nothing that either side has done in that terrible conflict comes close to the routine brutality of ISIS.

Karim couldn’t help expressing bitterness about this. “I don’t see any attention from the rest of the world,” he said. “In one day, they killed more than two thousand Yazidi in Sinjar, and the whole world says, ‘Save Gaza, save Gaza.’ ”

Yesterday, a senior U.S. official told me that the Obama Administration is contemplating an airlift, coördinated with the United Nations, of humanitarian supplies by C-130 transport planes to the Yazidis hiding in the Sinjar mountains. There are at least twenty thousand and perhaps as many as a hundred thousand of them, including some peshmerga militiamen providing a thin cover of protection. The U.N. has reported that dozens of children have died of thirst in the heat. ISIS controls the entrance to the mountains. Iraqi helicopters have dropped some supplies, including food and water, but the refugees are hard to find and hard to reach.

It was encouraging to learn that humanitarian supplies might be on the way, but we always seem to be at least a step behind as ISIS rolls over local forces and consolidates power. ISIS is not Al Qaeda. It operates like an army, taking territory, creating a state. The aim of the Sinjar operation seems to be control of the Mosul Dam, the largest dam in Iraq, which provides electricity to Mosul, Baghdad, and much of the country. According to one expert, if ISIS takes the dam, which is located on the Tigris River, it would have the means to put Mosul under thirty metres of water, and Baghdad under five. Other nearby targets could include the Kurdish cities of Erbil and Dohuk. Karim reported that residents of Dohuk, inundated with refugees, felt not just a sense of responsibility for Sinjar but also alarm, and that they were stocking up on supplies in case of an attack.

One way to protect the innocent and hurt those who are terrorizing them would be for the U.S. to launch air strikes on ISIS positions. That option has been discussed within the administration since the fall of Mosul, in June, but it runs against President Obama’s foreign-policy tendencies. “The President’s first instinct is, ‘Let’s help them to do it,’ ” the official told me. “The minute we do something, it changes the game.” This time, unlike in Syria, it isn’t hard to figure out how to “help them to do it”: send arms to the Kurds, America’s only secular-minded, pluralistic Muslim allies in the region, and the only force in the area with the means and the will to protect thousands of lives. (Dexter Filkins wrote, on Monday, about the possibility of American military aid to the Kurds.) Perhaps the U.S., Europe, and the U.N. can’t or won’t prevent genocide in northwestern Iraq, but the Kurds can. The fact that the peshmerga were outgunned by ISIS and ran out of ammunition in Sinjar says that we are a step behind on this front, too. According to the Times, Washington has turned down Kurdish requests for American weapons for fear of alienating and undermining Iraq’s central government in Baghdad.

It seems delusional to imagine that there is such a thing as an Iraqi central government that should be given priority over stopping ISIS and preventing a massacre. That dream of the American project in Iraq is gone. But perhaps the Obama Administration is being more realistic. Yesterday, I also learned that the U.S. is, in fact, sending arms to the Kurds—just not openly. This was even more welcome news, though it’s too bad that the weapons didn’t reach the peshmerga in time to defend Sinjar. The U.S. Joint Operation Center in Erbil is helping peshmerga ground troops and the Iraqi air force to coordinate attacks on ISIS, providing intelligence from the sky. It’s a breakthrough that the Kurds and the Iraqis are cooperating at all. “For the moment,” the senior official said. “And it could all fall apart, because it’s lightning in a bottle.”

The official said that peshmerga forces are organizing to retake Sinjar. Karim heard the same thing in Dohuk, and he said that he wants to be in the first group that returns to his hometown. Meanwhile, he’s volunteering with the American medical charity he used to work for, helping other refugees in Dohuk. He told his children that they’re on an extended vacation in Kurdistan.