The Talib looked as ragged as his outpost, a trailer banked on a snowy mountain pass. Holes were bored into its sides to ventilate a sputtering wood stove.

Upon seeing foreigners, the Talib, with an unkempt beard and layers of ill-fitting sweaters, ordered us out of the car.

For more than an hour, my colleague Bryan Denton and I waited on the trailer floor as he reviewed our documents. Beside him, two guards slept beneath heaped blankets. It smelled as if they had been there a while.

The Talib asked questions: Why had we come to Afghanistan? Where were we going? What were we doing?

We told him what we had told so many other Taliban members. I covered the war as a New York Times correspondent and bureau chief. Now I wanted to see the war from another perspective, to see what lessons — and secrets — the United States left behind.

I began to wonder if our luck had run out. Bryan turned to me and frowned.

The guard began recording us with his phone, sending our hearts racing. Almost no recording of a foreigner in similar circumstances has ended well this century.

But the Talib had other things on his mind.

“Can you please indicate that you have been treated well, and that no harm has come to you?” he asked, presumably collecting evidence in case we complained to his superiors.

One of the stranger things about our travels was how freely the Taliban allowed us to explore. For most of the war, they had shot, bombed or abducted any foreigner they could find. Times colleagues had been kidnapped or killed.

Yet no matter where we were, if we produced our paperwork, we were granted access to places that few foreigners had ventured in nearly two decades: the other side of the war.

We spent nights in half-constructed buildings, in barren deserts and perched on the edge of raging rivers. We interviewed hundreds of people and surveyed more than 1,000 others about war crimes committed by American allies.

I often think of this moment in relation to Vietnam. In that war, decades passed before the United States engaged its former enemy. By then, parts of history were lost.

Here is what we learned.

The Taliban didn’t win so much as the U.S. lost.

Time and again, we found, the Americans set the stage for their own defeat well before the Taliban marched to power in August 2021.

The United States empowered warlords and criminals to conduct the war on its behalf, individuals who inspired so much hatred that their very presence became a Taliban recruiting tool. This propensity was embodied by no one more than Lt. Gen. Abdul Raziq, the police chief of Kandahar Province.

The Americans turned allies into enemies.

By blindly trampling into places they did not understand, the Americans seeded hatred. Errant airstrikes not only killed innocents. They killed American allies — the very people who supported them the most.

In the rugged region of Nuristan, we traced the origins of one of the deadliest assaults on American soldiers. We discovered that American troops had created the enemies that they feared the most — and in places that they never needed to be.

The Taliban declared an amnesty, and an end to poppy.

After the war, the Taliban declared that, no matter which side you had been on, the fighting was over. Former enemies were prohibited from settling scores — and for the most part people listened.

The Taliban has also declared an end to poppy, seemingly accomplishing one of Washington’s key war goals.

The district, Bakwa, had once been a barely inhabited stretch of desert. But thanks to American efforts to eradicate poppy — and the opium trade — people had flocked to the desert district, where the Taliban embraced them.

The war was decided long before it was over.

President Biden blames the Afghan Army for crumbling so quickly. President-elect Donald J. Trump blames Mr. Biden.

Both versions ignore the history in places like the north of Afghanistan, a region where values like democracy and women’s rights might have actually lasted.

There, the United States empowered militias to fight the Taliban. Instead, these groups tortured, kidnapped and massacred civilians. They created such hatred toward the Afghan government and its American allies that people turned to the Taliban.

Before the Americans withdrew, the Taliban were already negotiating their rise to power.

The Taliban were inching closer, encroaching on land that had once seemed secure, the American officer warned. Four of his men had just been killed, and he needed Afghans willing to fight back.

“Who will stand up?” the officer implored a crowd of 150 Afghan elders.

The people in Kunduz Province were largely supportive of the Americans and opposed to the Taliban. But recruiting police officers was slow going and, by the summer of 2009, local officials and the American officer — a lieutenant colonel from the Georgia National Guard — landed on a risky approach: hiring private militias.

A murmur of discontent passed through the crowd.

“I don’t think this is a good idea,” an old man stood up and said, according to four people at the meeting. “We have seen this before. The militias will become a bigger problem than the Taliban.”

Over the grumbling, a onetime warlord named Mohammad Omar sprung up and denounced the others as cowards.

“I will fight the Taliban!” he shouted.

The gathering in Kunduz, in northern Afghanistan, is not registered in any official history of the war. But people across the province say this seemingly unremarkable moment reshaped the conflict in ways that Washington has never truly understood.

For years, the Americans supported militias in the north to fight the Taliban. But the effort backfired — those groups preyed on the populace with such cruelty that they turned a one-time stronghold of the United States into a bastion of the insurgency. People came to see the militias, and by extensions the Americans, as a source of torment, not salvation.

Mr. Omar, for example, who was known as the Wall Breaker, became the poster child of an abusive militia commander, marauding his way into local lore by robbing, kidnapping and killing rivals and neighbors under the auspices of keeping them safe from the Taliban.

The consequences came to a head during the chaotic American withdrawal in 2021. The north was expected to be America’s rear guard, a place where values like democracy and women’s rights might have taken hold.

Instead, it capitulated in a matter of days — the first region to fall to the Taliban.

President-elect Donald J. Trump has blamed President Biden for the messy end to America’s longest war, vowing to fire “every single senior official” responsible for the disastrous exit. Mr. Biden, by contrast, blames the Afghans for surrendering to the Taliban so quickly.

“Political leaders gave up and fled the country,” Mr. Biden said after the withdrawal. “The Afghan military collapsed.”

But both renderings miss a more fundamental reason for the rapid fall: In places like Kunduz, a New York Times investigation found, the United States set the conditions for its defeat long before the Afghan soldiers laid down their arms.

For years, the Americans helped recruit, train and pay for lawless bands of militias that pillaged homes and laid waste to entire communities. The militias tortured civilians, kidnapped for ransom, massacred dozens in vendetta killings and razed entire villages, sowing more than a decade of hatred toward the Afghan government and its American allies.

The Afghan Army, already overwhelmed, recognized that it was defending a government with vanishingly little support. So, when the advancing Taliban offered Afghan soldiers a choice — their lives for their weapons — they lay down arms.

The regions plundered by Mr. Omar and other warlords were active battlefields during the war, mostly off limits to outsiders. But more than 50 interviews, conducted in Kunduz over 18 months, showed how American support for the militias spelled disaster, not just in the province but also across the rest of northern Afghanistan.

That state-sponsored misery was central to how the United States and its Afghan partners lost the north — and how, despite two decades and $2 trillion in American money, Afghanistan fell.

Other Times investigations this year have revealed how the United States underwrote atrocities by Afghan forces and recklessly killed its own allies, essentially authoring its own defeat in Afghanistan.

The fall of Kunduz in 2021 was the final word on another unforced American error — its use of criminals to carry out operations against the Taliban.

“The militias shot at civilians and killed innocents,” said Rahim Jan, whose mother, father and two brothers were killed by Mr. Omar, which other villagers confirmed. With no other choice, he said, “we supported the Taliban, because they fought the militias.”

Even the Taliban, normally eager to boast of battlefield exploits, credit their victory in the province to American missteps.

“The U.S. empowered bandits and murderers in the name of counterinsurgency,” said Matiullah Rohani, a former Taliban commander and the current minister of information and culture in Kunduz. “But it only pushed more people into the hands of the Taliban.”

Human rights groups, academics and journalists have published numerous accounts of atrocities by militias. But the extent of the abuse, and how it helped enable the Taliban’s swift takeover of Afghanistan, is a story the Americans left behind when they abandoned the country three years ago.

Today, with the militias gone, the scale of their acts — in both human and political costs — is visible.

Previous accounts have blamed Afghan officials in the north for raising their own militias. But The Times found that the United States had recruited militias in Kunduz far earlier than was known, with a fallout far worse than American officials have acknowledged.

During its 20-year war in Afghanistan, the United States pushed an ever-evolving series of programs to recruit, train and support local resistance to the Taliban. Some formally created armed groups under the auspices of the police, while other backing was ad hoc, with money and training provided here and there. In many cases, the Afghan government doled out American cash, giving militias the imprimatur of Washington’s support.

Almost all of the efforts were problematic. Militias soon grew too powerful to disarm. And while they did fight the Taliban, they fought one another even more, creating the kind of civil war turmoil that first helped bring the Taliban to power in the 1990s. Some Afghans were so disgusted by the predatory militias that they began to see the Taliban as their defenders and joined the insurgency.

One of the first militias was born in the Kunduz district of Khanabad, the brainchild of the Georgia National Guard officer desperate to beat back the Taliban. And one of the earliest efforts involved Mr. Omar, the Wall Breaker.

“There was no doubt in my mind that Mr. Omar was a leader in that community,” said the now-retired officer, Lt. Col. Kenneth Payne, of the Second Battalion, 121st Infantry Regiment of Georgia’s 48th infantry brigade combat team. “And I firmly believe that, at the time, he was saying all the right things.”

Colonel Payne had not been sent to the north to recruit militias. He was there to mentor the police. But he had a wide remit, and a big idea. He decided that activating Mr. Omar’s group was worth the risk.

“It was almost like, ‘If this works, if this is better for me, where I will get an advantage, then I will do it,’” he said.

Instead, he wound up unwittingly supporting the only group in the region less popular than the Taliban.

The Wall Breaker

Months after the summer meeting, a Taliban fighter lay against the floor of a collapsed guesthouse. Outside, Mr. Omar, the newly minted militia leader, paced the street.

“Come out now, or I will blow the walls of this house down!” he shouted into a megaphone, as his men prepped mortars, witnesses said. “I am the Wall Breaker!”

The insurgent weathered round after round of mortars, each one collapsing nearby homes and terrifying residents with the indiscriminate explosions.

Finally, Mr. Omar retreated with his men, fearful that the Taliban might send reinforcements. But on the way out of town, for good measure, his militia looted a local store and roughed up a few locals, residents said, actions that turned much of the community against him.

Mr. Omar had waged an all-day battle, blasting his way through an entire village, to chase down a single Taliban fighter. And still, somehow, his target had survived.

But the Wall Breaker moniker stuck. The name captured Mr. Omar’s capacity for wanton violence, though not necessarily effectiveness.

And that early foray was among his least offensive, many locals say.

In another early mission, in a neighboring district, he stole so brazenly and abused so widely that residents cite it as the moment the entire area turned toward the Taliban. “He even took people’s dogs,” one recalled.

Mr. Omar, who had first taken up arms against the Russians decades before, used his renewed power to exact vengeance on his enemies from past wars and past decades.

Akhtar Mohammad said that his father, uncle and brother had been rounded up and summarily executed, ostensibly for attacking Mr. Omar’s convoy with a roadside bomb. But Mr. Mohammad denied that his relatives were involved in the bombing, which he said was just pretext; the two families had feuded for three decades.

“Being part of a militia meant having the power and authority to settle scores,” Mr. Mohammad said.

In Colonel Payne’s estimation, “things went very well for a while.” But his deployment ended soon after Mr. Omar’s militia began and the area “had a hard time after we left,” he said.

“It really bothered me because I thought we had made a difference,” he added.

The United States knew about the debacle unfolding in Kunduz. A diplomatic cable from the U.S. Embassy in November 2009 emphasized the importance of controlling the militias. If left to their own devices, they could “divide Afghan communities and spark additional violence,” the cable noted.

Two months later, the embassy seemed to confirm those fears: The government had no power over the militias, which fought among themselves and forced locals to pay them illegal taxes.

The cable mentioned Mr. Omar’s role in the chaos, but blamed an overzealous Afghan governor for hiring him. The diplomats seemed unaware that the Americans had empowered Mr. Omar themselves.

In 2013, four years after helping to arm the likes of the Wall Breaker in Kunduz, the United States left the north, handing control of security, and the militias, to the Afghan government.

In the criminal free-for-all that blossomed, new commanders emerged even worse than Mr. Omar. They leveled villages and massacred families, and fought one another, too: over territory or perceived slights.

The Times spoke with dozens of families who had lost loved ones to those men and others, killings that tallied into the hundreds.

Forced conscription was common, they said. Men were killed for refusing to join one militia or another. Charges of supporting the Taliban were leveled against those who refused to pay taxes, and many were jailed.

“The militias would label anyone they didn’t like ‘Taliban,’ and then abuse them so much they had no choice but to join the Taliban,” said Mohammad Farid, a shopkeeper who said he was imprisoned for refusing to pay Mr. Omar a share of the proceeds from the sale of his store.

The Americans did not direct the abuse, but they funded the government with billions of dollars in cash and weapons, which officials then used to hire and arm the militias. As far as the villagers were concerned, this was an American project. And the Taliban increasingly seemed like a better option.

Shahd Mohammad, a tailor by trade, said he endured more than a year of beatings and abuse before he finally sold his shop in 2013, moved his family to another district and joined the Taliban.

For the next six years, he led a unit focused on fighting the militias in Khanabad.

“I went from living my life as a tailor to fighting on the front lines,” he said.

The Taliban Take Advantage

President Ashraf Ghani took office in Afghanistan in 2014 and realized the militias were running amok. With the Americans by his side, he loudly promised to bring security to Kunduz by bringing people like the Wall Breaker under control.

Some militias, now maligned in public, soured on the government, former Afghan officials said. Some militias even switched sides, joining forces with the Taliban.

Seizing the moment, Taliban commanders began secretly calling militia leaders, sowing distrust by telling them that the government viewed them as the enemy, according to Taliban officials and former Afghan officials with access to classified intercepts. They, like some others, spoke on condition of anonymity because they feared repercussions.

The psychological tactic worked. Some militias stopped fighting for the government, while others kept clashing with one another, clearing the battlefield for the Taliban.

“The split between the militias was crucial for us,” said Hesmatullah Zalmay, a Taliban commander in Kunduz.

Within a year of Mr. Ghani’s threat to curtail the militias, Kunduz was on the verge of collapse.

It was too late. In August 2015, the Taliban stormed Kunduz City. Government forces and its militias fled until American airstrikes and special forces could help them retake the city.

Far from drawing lessons from the failed militia strategies, the Afghan government doubled down. To maintain order, Mr. Ghani’s government turned to a man even more ruthless than the Wall Breaker.

Haji Fateh

In a province shattered by ethnic and political divides, where factions of factions fought other factions, everyone agreed on one thing: Haji Fateh was the worst, most notoriously violent of all the militia commanders.

Accounts of his medieval torture methods — branding people with hot metal rods, burying them alive or keeping them chained in underground dungeons — still haunt the residents of Kunduz.

Mr. Fateh was widely seen as a scourge, a villain who killed innocents and charged their families to retrieve the bodies.

He was also an ally of the Afghan government and, by extension, their American backers.

Two former Afghan officials and several former militia commanders described years of government support for Mr. Fateh.

“We had a complicated relationship,” said one former high-ranking government official in Kunduz. “When the district came under attack, we gave him money and weapons to fight.”

The transfers were conducted in secret, he said, because Mr. Fateh was a wanted man.

Before the Taliban emptied the prisons in Kunduz during their brief takeover, Mr. Fateh had been locked up for killing a police officer while robbing a Kabul Bank truck.

“We supported him, yes, but it wasn’t like he could come to the governor’s house,” the official said.

How much the United States knew about the payments to Mr. Fateh is unclear. The money was given at a time when Afghan officials were under heavy pressure from Washington to take charge of their own security. The Pentagon did not respond to a list of questions about the militias.

After fleeing prison, Mr. Fateh set down roots in the braided hillsides of Deh Wayran, an area that was largely free of the Taliban.

He operated from a torture castle, according to residents, and demanded ransom payments for his kidnapping victims — men like Haji Wazir, a contractor for the Americans who said he was nearly starved to death by Mr. Fateh.

Mr. Fateh’s criminal empire was built on cruelty and swept up entire communities as he waged a brutal turf war with a rival militia.

Dozens died in scorched-earth battles between the two sides. Militias fired rockets and mortars into hillside villages and laced roads with bombs. They blamed the attacks on the Taliban, though they had no real presence there.

Almost nobody in Deh Wayran worried about the Taliban, residents said. To the contrary, they worried about the fight between two ostensible American allies.

Gul Afraz lived with her family in the village of Dana, a small community of Tajik families numbering fewer than 150 people.

Mr. Fateh planted roadside bombs that killed her son and two of her nephews, she said. Fearing that the village might take revenge, Mr. Fateh bulldozed every home there, villagers said, sending survivors fleeing.

Rival militiamen moved in, committing their own offenses, a tit-for-tat brutality that pushed more of the locals who remained to support the one group that wasn’t murdering them — the Taliban.

Within a year of Mr. Fateh’s arrival, the entire village had all but been wiped out.

“There was no Taliban here at first,” Ms. Afraz said, “but I am so grateful they are here now.”

Mr. Fateh operated with impunity, running checkpoints along the highway and extorting motorists of thousands of dollars a day, according to his former friends who remain in the region.

In a cynical twist, Mr. Fateh’s abuses made him ever more essential to the government: The more he pushed people into the arms of the Taliban, the more the government needed him to fight them.

The chief of police, the intelligence service and the army showered him with money and munitions, according to the former government officials and militia commanders. Even the highly trained Afghan Special Operations forces were supporting him.

And because the Afghan government was practically insolvent, it meant the Americans were paying for it all.

“We tried to capture him many times,” said Sadat, a former special operations commander, who like many Afghans goes by a single name. “But then the government began to support him.”

Prosecutors in Khanabad issued more than 100 warrants for Mr. Fateh’s arrest as complaints of robbery, extortion and murder poured in. But the local authorities refused to act.

One prosecutor gave his federal counterparts in the Ghani government 150 case files bearing evidence of Mr. Fateh’s crimes, to no avail. Mr. Fateh was untouchable, and he knew it.

One day in 2020, the Shiite owner of an ice cream store in Khanabad complained that Mr. Fateh should stop stealing his ice cream. Mr. Fateh had the shop owner beaten in the street.

In response, Haider Jafari, a local Shiite leader, said he had no choice but to confront him. Mr. Fateh responded by shooting him in the chest, wounding but not killing him.

Mr. Fateh then burned Shiite homes in the town and ordered Mr. Jafari to flee. To reinforce his point, Mr. Fateh murdered his nephew, Mr. Jafari said.

“We went directly to the governor, and he could not do anything,” Mr. Jafari said. “We began to support the Taliban after that.”

American Withdrawal and the Fall of Kunduz

In February 2020, when the Trump administration reached a peace deal with the Taliban, the die was cast: the Americans were leaving.

The Taliban went from district to district, using elders to encourage the Afghan Army to lay down its arms. It was not much of a negotiation. Thanks to the militias, the Taliban were stronger than ever, and there was no good will left for the government.

By the time the United States announced its timetable for the withdrawal in 2021, the Taliban had all but taken most districts in Kunduz.

Khanabad was different, in part because men like Mr. Fateh and Mr. Omar dug in.

The Taliban and the government traded control of Khanabad three times during the second week of June.

Mr. Biden met Mr. Ghani in Washington that month, insisting that the war’s final act had not yet been written.

“Afghans are going to have to decide their future,” Mr. Biden said.

Mr. Fateh apparently did not share that optimism. Taliban officials say he tried to switch sides and even called a Taliban commander to offer his cooperation. But by then, the government was on its heels, and the Taliban saw no point in granting him quarter.

The militias abandoned Khanabad for Kunduz City, taking residence in whatever areas they could find. Mr. Fateh positioned himself in a home near the eastern edge of the city. Mr. Omar emptied a madrasa of students and claimed it as his headquarters.

Afghan commandos were dispatched to Kunduz to beat back the Taliban.

“They have the capacity. They have the forces. They have the equipment. The question is: Will they do it?” Mr. Biden said in July 2021. “The likelihood there’s going to be the Taliban overrunning everything and owning the whole country is highly unlikely.”

But the fight in Kunduz was over before it began. Even as commandos fought to defend the city, the Taliban were negotiating with the Afghan Army to take over the province, Taliban officials said.

Everyone saw the writing on the wall. Even residents who loathed the Taliban were tired of years of abuse at the hands of militias. The Afghan military was easily persuaded not to die for a lost cause, former Afghan officials said.

“In the end, the militias were the undoing of the government,” said Abdul Rauf Charsari, a former police commander in Kunduz.

Aftermath

Some of the most notorious warlords and criminals who brought such misery to Kunduz — and ultimately did more to support the Taliban than defeat them — faded away without a final battle or trial.

Mr. Omar, the Wall Breaker, died of natural causes not long after the Taliban took over.

Haji Fateh fled to safety as the province fell and resettled in Iran, where he lives in a swanky home paid for by the money he earned brutalizing the people of Kunduz, according to one of his friends.

Mr. Fateh could not be reached for comment, but he welcomes visitors regularly for lavish meals or tea, said the friend, speaking on condition of anonymity out of fear of incurring his wrath.

Among his most frequent guests, the friend said, are former Afghan government officials, hoping to convince him once more to take up arms on their behalf.