The Guardian reports: Even by Afghanistan‘s high standards, the massacre of Shia worshippers in Kabul on Tuesday 6 December was an act of stomach-churning brutality. A suicide bomber posing as a pilgrim on Ashura, one of the holiest days of the calendar of Shia Islam, had inveigled his way into the middle of a packed crowd of men, women and children. Witnesses watching from the rooftop of the nearby Abu Fazal shrine said body parts flew up into the air near the epicentre of the blast when the unknown bomber detonated himself.

The clearing smoke revealed a scene strewn with lifeless and often mangled bodies, lying in circles around the blackened area of tarmac where the bomber had stood. A young girl who had somehow miraculously survived was snapped by a photographer wailing into the air. Among the 55 killed there were no police officers or soldiers or anyone who might remotely be considered a “legitimate” target of the Taliban-led war against the Afghan government.

The Taliban itself was quick to condemn the attack in strong terms, while an extremist Pakistan-based movement called Lashkar- e-Jhangvi al Almiv has been fingered. If it really was a unilateral operation launched without the consent of the Taliban’s leadership it is another worrying sign of how the insurgency in Afghanistan is spinning out of control, becoming crueller and ever more willing to inflict horrendous damage on ordinary civilians.

But not everyone thinks such horrors are an entirely bad thing. Indeed, some within the US war machine have long argued the emergence of a nastier insurgency could be really quite useful for Nato‘s war aims. So useful, in fact, that foreign forces should try to encourage such behaviour.

One of them was Peter Lavoy, a former chairman of the US National Intelligence Council, the body that examines data from across the US government’s intelligence gathering machine and turns it into high-grade analysis that is rarely discussed publicly. At a closed-door meeting with ambassadors at Nato headquarters in Brussels in December 2008, Lavoy spelled out a strategy for winning the war in Afghanistan that has never been uttered publicly: “The international community should put intense pressure on the Taliban in 2009 in order to bring out their more violent and ideologically radical tendencies,” he said, according to a State Department note-taker in the room. “This will alienate the population and give us an opportunity to separate the Taliban from the population.”

His words, which we only know courtesy of WikiLeaks, are extraordinary because they have been proven at least partially right. They also differ fundamentally from the publicly stated strategy in Afghanistan. Known as population-centric counterinsurgency, or Coin, the fundamental principle is that foreign forces should try to keep ordinary Afghans safe from insurgents and thereby win their support.

The idea that Nato may actually be trying to make the population less secure appalls observers. “It just goes completely against the ethos of the American military not to take more risks in order to protect civilians,” says John Nagl, a retired lieutenant-colonel who co-wrote the US army’s field manual on countering guerrilla warfare. “I find it hard to believe elements of the US military would want to deliberately put more risk on to civilians.”

But behind the scenes, powerful voices continue to argue for a harder-edged strategy that makes the lives of ordinary Afghans more miserable, not less. Michael Semple, a regional expert on the Taliban, says it is an outlook he runs across in discussions with Nato officials: “I have heard serious, thinking officers articulate the idea that provoking Taliban fighters into acts of extreme violence against the population could be taken as a sign of Coin progress, prior to the final victory when the people turn against them.”