During the mid-1960s, America's goal during a crucial stage in the Vietnam war was to defeat the enemy militarily. But it had no realistic political strategy to underpin the goal, and it was this which ultimately led to failure.
America's strategy in Afghanistan is now suffering from a similar weakness. Barack Obama made the edgy claim this week that the US army is stabilising the military situation, but neither he nor his national security advisers show any signs of understanding the speed at which,politically, the US is losing ground.
Again and again in Kabul one hears Afghans say that the Taliban may not be liked, but that the Afghan government and its US allies are increasingly distrusted, even hated, by the mass of the population. It is this rapidly increasing disaffection, underestimated by foreign governments, that enables a maximum of 25,000 Taliban to hold their own against 140,000 US-led foreign troops in addition to the Afghan government's army and police. Instead of giving priority to seeking a feasible political approach, the current US strategy is to eliminate the Taliban as an effective military organisation. American generals claim they are beginning to turn the tide by an offensive against enemy strongholds in southern Afghanistan and through the systematic killing of local Taliban commanders by US special forces.
Body counts of enemy dead, a notorious and discredited measure of success in Vietnam, are back in favour. The US military proudly announced this week that it had killed 952 Taliban and captured 2,469 in the 90 days up to the beginning of December. One general boasted: "Every 24 hours on average, we're killing three to five mid-level enemy leaders."
Bizarrely, it is the US commander in Afghanistan, David Petraeus, who is leader of this campaign which aims for success through military force alone. Yet it was General Petraeus, lauded as the architect of the military surge in Iraq, who emphasised that in counter-insurgency the US cannot kill its way to victory. As the author of the much-praised field manual for the US armed forces, he stated that success in counter-insurgency is four-fifths political and only one-fifth military action.
There have been important changes on the ground in Afghanistan over the past year, but many of them have been in favour of the Taliban. As US forces concentrate on the south, the Taliban have taken over swathes of territory in northern and eastern Afghanistan, far from their areas of core support. Kabul is a peaceful island but all the roads in and out are cut or vulnerable to attack.
In 2001, just before the ground war started, when the Taliban controlled most of Afghanistan, I travelled from just north of Kabul through the Hindu Kush mountains through Badakhshan to the border with neighbouring Tajikistan. The terrain was very bad; part of the time we had to drive along river beds or tracks carved out of the sides of the mountains. The journey took us four days, but there were no Taliban and no threat of them.
I could not make the same journey today, because the Taliban or their allies are making inroads in districts they did not control even at the height of their power. In Kabul, government authority ends at the last police station in the south of the capital. Beyond this Taliban patrols on motorcycles set up mobile checkpoints and kill or kidnap anybody associated with the Afghan government or the foreign presence. People leave their mobile phones behind in case the Taliban should find incriminating numbers on them.
In much of Afghanistan, the government does not exist or only in the form of local racketeers and gunmen, often wearing police or army uniforms. A few weeks ago I was driving up the Salang Pass, a vital and supposedly secure route linking Kabul to the north of the country, when we were stopped by a group of men with guns in ragged military uniforms who claimed they were collecting a hitherto unheard of municipal road tax. Afghan drivers said they thought they were simply a gang of bandits but sounded unsurprised and paid up anyway.
The pervasive corruption of the Afghan administration only gets worse. Every election is more corrupt than the one before. The latest parliamentary election, final results of which were announced last month, was peculiarly fraudulent. "I don't think anybody will bother to vote in the next poll," said one candidate resignedly. Even counting fake votes, only a third of the electorate voted this time.
The current US policy would only work if it did not matter what ordinary Afghans think. But all the evidence since 2001 is that it matters a great deal. The resurrection of the Taliban was not inevitable and was largely provoked by the takeover of local administration by former warlords and militia leaders. The wholesale alienation of much of the population is even more recent and enables the Taliban to withstand the heavy casualties they undoubtedly suffer from the US-led night raids or air strikes.
Hostility to the government is not confined to farmers who have to pay off the local police. It was strange to sit in the office of a prosperous estate agent in Kabul and hear him say: "It is impossible for this situation to continue without a revolution." He pointed to some labourers outside his window and said, "Those men earn $5 to $6 a day but for them to rent a decent house for their families would cost $1,000 a month."
The generals, diplomats, aid workers, security men and all the others who make up a sort of colonial elite in Kabul may be dancing on thinner ice than they imagine. Afghans may work for them but do not like them. One highly educated Afghan who worked for a US aid agency recalled bitterly how "they treated us Afghans as third-class citizens, packed five or six to a room while each foreigner earned five times what we did and had a room of his own".
Afghans are adept at concealing their real views. A government official was giving me a bland account of his ministry's activities. Bored, I asked if there was anything he would like to say to me unattributably. "Well", he said, without changing his smooth tone of voice, "there is no chance of any progress here so long as our country is run by gangsters and warlords." But it is to keep these same people in power that the US and Britain are now fighting a war.