Nato: End To Afghan Chapter Is In Sight

"All in together, all out together" in the words of one defence expert, summarises what the Nato leaders have agreed in Chicago.

After a decade of fighting and more than 3,000 troops killed, the summit declaration stresses: "The irreversible transition of full security responsibility from the International Security Assistance Force (ISAF) to the Afghan National Security Forces is on track for completion by the end of 2014."

Beyond that date David Cameron made a point of stating that "Nato will not establish a new combat mission".

Until then though British troops will continue to fight, even once the Afghan government takes charge of security across the whole country sometime in the middle of 2013.

So the troops are coming home as the politicians wanted, "gradually and responsibly" according to the Nato statement. But that will not be the end of the Nato nations' entanglement in Afghanistan.

The summit participants also underwrote a commitment after 2015 so that "Afghanistan will not stand alone"' as President Obama put it.

A pledging conference for the civilian reconstruction of the country will take place soon in Tokyo.

Here in Chicago the 28 Nato countries and other ISAF contributors such as Australia, Japan and the UAE committed to a $4.2bn (£2.6bn) annual fund to sustain Afghan security in 2015, 2016 and 2017.

Non-US nations will contribute $1.2bn (£760,000) a year to this; the UK has pledged a share of around £70m. Separately Britain is setting up an officer training college for the Afghan forces dubbed "Sandhurst in the sand".

"It's a significant amount", the British Prime Minister acknowledged, "but a fraction of the cost of combat".

More sobering still is the reason why such heavy security spending will still be needed.

British Defence Secretary Philip Hammond confirmed on Sky News that the terrorist threat will not have been entirely eliminated by time of the pull out.

And the Taliban will still be there too - even if Mr Cameron urged them "you can't win on the battlefield; stop fighting and start talking". So much for the allies lofty ambition after 9/11 to eliminate al Qaeda and the culture which incubated it in Afghanistan.

Nor will the withdrawal be easy in practice. The US and Pakistan Presidents flew home without a deal to re-open the southern line of communication.

They were shut down by Pakistan last November following an American anti-terror attack which left more than twenty Pakistani soldiers dead.

The Pakistanis want an apology and an end to US drone attacks on their soil. Neither seems likely. More probable is an agreed high tariff for each US vehicle which passes through.

One hopeful development is that Presidents Obama and Zardari at last greeted each other in public during a final photo call, having been locked in a diplomatic standoff for the previous two days.

More blood and treasure will be expended, but Nato believes the end of its Afghan chapter is in sight.

Significantly for the future, countries here also agree that their experiences in Afghanistan have only convinced them that this Alliance and the cooperation it brokers are the "bedrock" of their time going forward.