Simon Jenkins

One word shines through the spin surrounding this week’s Barack Obama policy review on Afgha-nistan. The word is exit.

Before he became president, Obama was much taken by the idea that Afghanistan was a good and winnable war, a usefully macho contrast to his retreatism on Iraq. But in a military briefing at the time, he asked what was the exit strategy from Kabul and was met with silence. He has got the point.

In Britain, Gordon Brown too has no answer. Whether speaking to troops in the field or to the House of Commons, he incants the unconvincing line that the war he is waging, and plainly not winning, against the Taliban is about “terrorism on the streets of Britain”.

He cannot believe this any more than do his listeners. His platitudinous references to Afghanistan in the counter-terrorism strategy launched yesterday are evidence of this, complete with its absurd insistence on “poppy eradication”.

This war remains what it was from the start, aggression against a foreign state intended to punish it for refusing to hand over the perpetrators of 9/11. It was later sanitised (largely by the British) as a liberal intervention to bring democracy and gender awareness to a poor people.

The American architect of the war, Donald Rumsfeld, had no such lofty ambition. He just wanted to hit hard and get out. It was Tony Blair and the neocons who saw the country as a testbed for their new philanthropic imperialism.

After nearly eight years of fighting, the original objective — to find Osama bin Laden — has eluded the strongest military coalition on earth, while liberal intervention is ever further from success. A British government has again sent an army to get stuck in a senseless war against Pashtuns. It never learns.

If Britain has forgotten, at least Obama appears to be learning from America’s equivalent example, Vietnam.

The drift to a repeat of that catastrophe is the last thing his presidency needs just now. He can see that the occupation of Afghanistan has made every mistake in the invader’s handbook.

It has been Vietnam for slow learners.

The good news from Washington is that Obama seems determined to stop all this. Under cover of a boost of 17,000 troops to Helmand, he hopes to suppress the violence for long enough to reach ramshackle deals with the Taliban, giving cover for withdrawal — first to Kabul and then out altogether, leaving local leaders to make some sort of peace with themselves, their insurgents and their neighbours.

This policy has mountains to climb.

The parallels with America’s last years in Saigon are foreboding.

The old maxims remain true: getting into a war is easy, getting out is hard. Obama seems to realise that the fate of America’s Afghan adventure has come to depend not on what Nato does or does not achieve, but on the good offices of the emergent Taliban and the stability of the currently shambolic regime in Islamabad.

As with the Russians so with the west: this poor, intensely private country will one day see off another invader who sought to reorganise its history with guns, bombs and money.

It has not worked. It was never going to work. Oh so painfully, we are now beginning to realise.