A more graphic demonstration of the intractable morass in Afghanistan it would have been difficult to imagine. On Tuesday, the Taliban attacked a police checkpoint in the far west of the country, killing three officers. These fighters then moved on to a nearby village where they executed three civilians whom they accused of spying for the government in Kabul. The Afghan security forces called in the US military for support. But in the subsequent air strikes, scores of innocent Afghan civilians, including women and children, were killed.

The US military had every right to go after the murderous Taliban. But this accidental bloodshed will merely increase the alienation of the local population and further undermine the authority of the central Afghan government.

The White House was planning to use yesterday's meeting with Hamid Karzai in Washington to exert some pressure on the Afghan president to stamp out corruption in his administration or risk losing US support. But such warnings rang hollow after the news of this massacre broke. With allies like this, the Afghan president will have wondered, who needs enemies? Yet the same question has probably crossed the mind of the Obama administration more than once. As our correspondent Patrick Cockburn wrote this week, seven and a half years of President Karzai's dysfunctional rule in Afghanistan has left the country in a truly appalling condition. Corruption is rampant and the economy is almost entirely dependent on illegal opium exports.

Very little aid money has reached the ordinary Afghans who desperately need it, while vast sums have gone to build lavish fortresses for aid workers and diplomats in Kabul. The repression of women continues, as demonstrated by a recent law enforcing the "marital rights" of husbands, passed to appease Shia hardliners. And, in the midst of this chaos, the Taliban insurgency is gaining in strength.

There is, however, still reason to believe that the situation can be retrieved. The new Western troops arriving in the country should help make the roads safer, enabling Afghans to travel in greater security. Paying police officers more should help stem corruption. And cutting off the Taliban's Pakistani supply lines would hobble the insurgency. To this extent, the new White House strategy of enhancing security and winning the backing of the ordinary Afghans is sensible. The White House is also doing the right thing in treating Afghanistan and Pakistan as a single security challenge.

And, as bleak as the security situation is, the fundamentals for improvement still exist. The Taliban is still generally unpopular in Afghanistan. It lacks broad appeal in Pakistan too. But the dilemma of how to defeat a guerrilla insurgency remains. Stand back and the insurgents gain more territory, prompting local communities to lose faith in the ability of the central government to protect them. Push aggressively and you risk civilian casualties, which erode the goodwill of the population.

Yesterday's carnage at least demonstrates that air strikes cannot be part of the solution. This is also true across the border in Pakistan, where strikes by unmanned US drones are fuelling anti-American resentment.

If some form of stability can be restored to this most dangerous of regions, it will be a long and difficult road for the US and its allies. The first step must be to ditch a military tactic that has already, surely, done more harm than good.