Patrick Cockburn writes: The United States’ announcement that it plans to end the combat role of its troops in Afghanistan earlier than expected, and before the end of next year, is a crucial milestone in the international forces’ retreat from the country. Coming after the French decision to go early, the US move looks like part of a panicky rush for the exit. More important, Afghans like to bet on winners, and the US action will convince many that these are increasingly likely to be the Taliban and Pakistan rather than the Afghan government. No wonder Nato officials looked so anxious as they pretended that the US action had not come as a nasty surprise.

The decision, revealed by the US Defense Secretary, Leon Panetta, with deliberate casualness to journalists on his plane, is an admission of failure. The US has an army of 90,000 soldiers in Afghanistan and is spending $100bn a year, but has still been unable to defeat 20,000-25,000 Taliban who receive no pay at all.

A little over 10 years ago, I was standing on a small hill by a ruined textile factory 40 miles north of Kabul watching the plumes of fire erupt on the skyline as US bombs and missiles exploded in the Taliban front line. In the next few weeks the Taliban government imploded and I was able to drive nervously but safely to Kabul and, soon after, to Kandahar.

It is an extraordinary turn-around that a decade later the Americans are departing and the Taliban are back in business. A leaked Nato report on interrogations of 4,000 captured Taliban, al-Qa’ida, foreign fighters and civilians shows that Taliban prisoners are in a confident mood. They believe their popular support is growing, Afghan government officials secretly collaborate with them, and, once foreign troops are gone, they believe they are going to win. The authors of the Nato report say “Afghan civilians frequently prefer Taliban governance over Giroa [Government of the Islamic Republic of Afghanistan] usually as a result of government corruption, ethnic bias and lack of connection with local religious and tribal leaders.” This enables the Taliban easily to recruit more fighters to replace their casualties.

As in Iraq, departing US troops will leave behind a very different political and military landscape in Afghanistan from the one they hoped to create. In the Iraqi case, power is held by Shia religious parties closely linked to Iran, which is the opposite of what the Americans wanted to see when they captured Baghdad in 2003. In the Afghan case, the government of Hamid Karzai has waning authority as the US steps back and Afghans take out insurance policies to ensure personal survival by making approaches to the Taliban. In both Iraq and Afghanistan, powerful US armies failed to impose their control or restore peace.