Shortly after the Taliban fell in Afghanistan, NPR correspondent Sarah Chayes found herself reporting a story she was sure had enormous implications for both that country and the United States.

She couldn’t get it on the air.

Five years later, in her new book, “The Punishment of Virtue: Inside Afghanistan After the Taliban,” Chayes returns to this unheard story. It’s a starting point for a detailed, highly personal exploration of the enormous price she believes the United States is paying for a mistake now so widely acknowledged it has become a cliche: intervening militarily with “no concept” of how to “create a working society after the intervention.”

It goes like this:

In December 2001, Chayes rushed across the Pakistani border in the company of a young fighter affiliated with the forces of Gul Agha Shirzai, a local warlord. Shirzai’s militiamen had just taken control of Kandahar, the fabled southern city that had been a key Taliban and al-Qaida stronghold. The takeover, Chayes knew, was in defiance of the orders of newly anointed Afghan President Hamid Karzai, who had designated another group to hold Kandahar.

What Chayes didn’t know was the role played by American Special Forces troops attached to Shirzai’s militia. She imagined the Special Forces guys cursing the renegade warlord, then saying: “They’re attacking, we’d better go along with them.” But when she asked her militiaman escort, “This kid looked at me and said, ‘The Americans? They told us to do it!’”

What a story, she thought: No sooner has the new central government taken power – representing the promise of a better life for the long-suffering Afghan people – than its authority is undermined by “American soldiers egging on a warlord to snatch Kandahar away from President Karzai.”

For whatever reasons, her editors saw it differently. They told her it was nothing but “squabbling among the Afghans” and cut it from her “All Things Considered” report.

Chayes, who grew up in Cambridge, Mass., is a slim woman in her mid-forties with an intense gaze and a deeply bicultural life. She left NPR in 2002, after her reporting tour in Afghanistan ended, and accepted an invitation from Karzai’s uncle to help run a fledgling nongovernmental organization called Afghans for Civil Society. At a recent book party in Bethesda, Md., she kept tugging at the straps of her little black dress as though it were an unfamiliar foreign garment – which, in a way, it is. In Afghanistan, she had long dressed like an Afghan man, the better to move around in a male-dominated society.

Earlier in the day, she’d been asked to appear on PBS’s “NewsHour.” There had been a horrific bombing in Kabul, and the question of the hour, she says, was “Why this uptick in violence now?”

Her answer: Actually, Afghan violence has been spiking higher and higher since late 2002. “You guys have just started to notice it.”

Chayes’ book represents a paradox of which its author is fully aware. She has used her years of non-journalistic experience to offer an intimate insider’s tour through a complex universe Americans need to understand – one in which warlordism, corruption and renewed Taliban activity have combined to undermine the “civil society” she was trying to nurture. Hers is the kind of fleshed-out portrait that even the best on-the-run journalism rarely provides.

Yet, in book form, her insights may come too late to influence the fate of her adopted home.

This is not to say she hasn’t been trying in other ways. “I’ve been saying this stuff steadily since late 2002,” she says: in op-eds, in speeches, in widely circulated e-mails and directly to every influential person she could collar. “Getting into these people’s offices and bossing them around” is how she describes these efforts, with a laugh. To get a sense of what she means, you need only read the chapter in which she hands Karzai an unsolicited eight-point plan for ridding Afghanistan of warlords.

One of her Afghans for Civil Society colleagues, she says, believes “that I actually don’t see obstacles,” so when one appears, “I get all outraged: How dare there be an obstacle in my way!”

There’s truth to this, but in the end, she’s not so obtuse. Experience has taught her, over and over, how formidable the obstacles to Afghan progress are.

At the book party, she passed around a photograph of Muhammad Akrem Khakrezwal, who was chief of police in Kandahar for much of the time she’s lived there. “Akrem won people over, and not just with words,” she writes of the man who became a close friend and ally and whose spirit permeates her book. “Akrem won them over because he did something. He was effective. And he had vision.”

In June 2005, he was assassinated. “The Punishment of Virtue” begins with a chapter on his funeral.