Barack Obama is set to reject the advice of the Pentagon by announcing on Wednesday night the withdrawal of up to 30,000 troops from Afghanistan by November next year, in time for the US presidential election.
The accelerated drawdown will dismay American and British commanders in Kabul, who have privately expressed concern that the White House is now being driven by political rather than military imperatives.
Obama's decision is aimed at placating an American public tired of a 10-year war that has cost 1,522 US lives. The killing of Osama bin Laden added impetus to calls to pull out.
Nato commanders led by General David Petraeus have set out the risks of withdrawing too many troops too soon, and warned Obama there has been no noticeable dividend from the death of the al-Qaida leader. They had urged him to keep in place the bulk of the extra 30,000 troops he committed to the "surge" until the end of 2012, so a drawdown can begin in 2013. That would give the military another full "fighting season" to attack Taliban strongholds and target insurgent leaders.
This year's fighting season, which is now underway, has shown that the Taliban is still strong, despite the pounding given to them over the winter by ISAF forces. In the first week of June, there were 701 security incidents across Afghanistan.
The withdrawal has created deep divisions in Washington. The defence secretary, Robert Gates, argued for a modest reduction – at one point as low as 2,000 – citing the advice of US commanders in Afghanistan that they need to protect gains made during the winter against the Taliban.
But senior White House staff, conscious that the president has an election to fight next year, argued in favour of a reduction that would send a signal to the US public that an end to the war is in sight.
The Associated Press reported that Obama could announce 10,000 troops to be brought home by the end of the year, and a further 20,000 next year – all of the 30,000 extra troops he ordered to Afghanistan as part of the "surge" in 2009. That would still leave about 70,000 troops, with all combat troops scheduled to leave by 2014, provided that Afghan forces are ready to take over.
Gates, who, along with secretary of state Hillary Clinton, was scheduled to meet Obama at the White House to finalise the details, acknowledged on Tuesday that US political considerations as well as conditions on the ground in Afghanistan contributed to the decision.
He said the war's unpopularity in the US and with Congress had to play a significant part in the president's thinking.