Praveen Swami is Associate Editor Frontline magazine, and also writes for its sister publication, The Hindu.

In the spring of 1839, the extraordinary Indian adventurer and spy, Mohan Lal Kashmiri, engineered one of the greatest intelligence coups of the 19th century: using nothing more lethal than cash and intrigue, he brought about the fall of Kandahar and secured the Afghan throne for Imperial Britain's chosen client, Shah Shuja-ul-Mulk.

Less than three years later, in the bitter winter of 1842, Kashmiri found himself working undercover in insurgent-held Kabul, seeking to ransom the remnants of his masters' once-magnificent army — children, women and men at threat of being sold as slaves in Central Asia.

For decades after, imperial historians agonised over the Afghan debacle of 1842, using tropes that still colour discourse on the country: religious fanaticism; treachery of native rulers; savagery of the tribal culture; primitiveness of its civilisation.

In a June 1842 paper, authored for the attention of the Governor-General in New Delhi, Kashmiri offered a simpler explanation. Britain's easy victory in Kandahar and Kabul, he recorded, persuaded commanders that "there was no necessity for wearing longer the airy garb of political civilities and promises." He concluded: "there are, in fact, such numerous instances of violating our commitments and deceiving the people in our political proceedings, within what I am acquainted with, that it would be hard to assemble them in one place."

Eleven years ago, the United States went to war in Afghanistan, promising to free its people from a despotic Islamist regime...