In spite of the commitments made at Tuesday's conference on the future of Afghanistan in Kabul, the current US counter-insurgency strategy (Coin) is likely to fail. The Taliban cannot be sufficiently weakened in Pashtun Afghanistan to coerce it to the negotiating table. America cannot win over sufficient numbers of the Afghan Pashtun on whom Coin depends. President Hamid Karzai's deeply corrupt government shows no signs of improvement. The Afghanistan army cannot stand up to the Taliban for many years, if ever. Pakistan's military continues to support its Afghan Taliban proxies. And the long-term Coin strategy and the far shorter US political timeline are incompatible.

President Barack Obama has promised to review the administration's Afghanistan policy in December. After this review the US should stop talking about exit strategies, and accept that the Taliban will inevitably control most of the Pashtun south. Instead Washington should move to ensure that north and west Afghanistan do not fall too, using for many years to come US air power and special forces – some 40,000-50,000 troops – along with the Afghan army and the help of like-minded nations. Such a de facto partition would be a profoundly disappointing outcome to America's 10 years in Afghanistan. But, regrettably, it is now the best that can realistically and responsibly be achieved.

This week media reports suggested another approach gaining favour: negotiation. But as CIA director Leon Panetta said recently about Taliban behaviour, why would they negotiate in good faith, if they think they are winning? Some instead think the US should withdraw all of its military forces over the next year. But that would be a major strategic defeat for the US and its partners, with negative global repercussions for many years to come.