A few days ago I confronted a class of politics and law students, their eagerness undimmed by erratic lighting. After all, this was the University of Kabul, not Oxford. Their questions focused on Nato's contribution to their country's security. Some reckoned that the coalition was not succeeding, and most seemed unaware that the alliance has twice affirmed its continuing support to Afghanistan after 2014, most recently at Chicago.

Their confusion was understandable. The electorates of Nato members are also confused. When Barack Obama visited on May 1, he delivered two messages: one to President Karzai promising co-operation after 2014; and the other, in a speech to his domestic electorate, promising the end of the war in the same year. We talk about an era of globalised communications, and yet our leaders try simultaneously to deliver different messages to different audiences. They confound not just “strategic communications” but strategy itself.

A second vignette: a meeting with human rights organisations in Afghanistan, their focus on corruption and the survival of old elites. Unlike the students, they did address Afghanistan's political processes and saw them as central to its security. The presidential election is also scheduled for 2014, but there is still no viable candidate to succeed Karzai, nor a political party to embed such a candidate. Many Afghans say there is time; the liberals realise there is not. And yet the freedom with which they voice their worries manifests the political and democratic gains they have made.

A final vignette also embodies optimism: an Afghan general, a large map spread on the ground, explained his theatre of operations and his capabilities. He was like Montgomery in the desert in 1942, with his divisional commanders clustered about him. He possessed the qualities of a natural leader, but he made a collective point. The Afghan National Army has developed as a fighting formation with astonishing speed. Its soldiers, not Nato's, are now taking the bulk of the casualties in clashes with the Taliban.

So-called “green on blue” attacks, such as that in which three British servicemen were killed by an Afghan policeman on Monday, have to be set against the steep decline in Isaf losses over the past year.

The Taliban are targeting the trust between Afghan forces and Nato's precisely because they can't achieve tactical success against the Afghan army.

War in Afghanistan has persisted for so long — more than 30 years — that most cannot remember life without it. What they tend to forget is how truly primitive Afghanistan remained in the “golden age” of the 1960s and 70s. War has brought unprecedented economic investment and political change. It is not just the liberal intelligentsia and elites who fear a reversion to the backwardness embodied by the Taliban, many of the rural people do too. A large proportion of the IEDs now defused by Nato forces are revealed by local Afghans.

Aware that counter-insurgency successes do not readily convert to political outcomes, Nato forces have increasingly forsworn the use of the word victory in their doctrines. But an opposite danger looms — that their nations see counter-insurgency as incapable of delivering success. Indubitably some areas will not be fully insurgent-free in December 2014. But the same is true of states that we do not see as vulnerable, including Turkey. Much of Afghanistan is palpably more secure than it was a year ago, not least Kabul and Helmand, as well as its increasing network of highways. The momentum has swung from the Taliban, and they know it. Coalition leaders, and their electorates, need to wake up to it; if they don't, they could still lose a war that is there to be won.

By arrangement with the Guardian