Camp Leatherneck (Afghanistan): US Marines will march out of Afghanistan by the thousands next year, winding down combat in the Taliban heartland and testing the
US view that Afghan forces are capable of leading the fight against a battered but not yet beaten insurgency in the country's southwestern reaches, senior US military officers say.

At the same time, US reinforcements will be sent to eastern Afghanistan in a bid to reverse recent gains by insurgents targeting Kabul, the capital.

General James F Amos, commandant of the Marine Corps, said in an interview that the number of Marines in Helmand province will drop "markedly" in 2012, and the role of those who stay will shift from countering the insurgency to training and advising the Afghan security forces.

The change suggests an early exit from Afghanistan for the Marine Corps, even as the prospects for solidifying their recent successes are uncertain.

"Am I OK with that? The answer is 'yes,'" Amos said. "We can't stay in Afghanistan forever." He added: "Will it work? I don't know."

At stake is President Barack Obama's pledge to win in Afghanistan the war he touted during his 2008 presidential campaign as worth fighting, while pledging to get out of Iraq.

Facing a stalemate in 2009, Obama ordered an extra 30,000 US troops to Afghanistan including about 10,000 Marines to Helmand province in the belief that if the Taliban were to
retake the government al-Qaida would soon return to the land from which it plotted the September 11, 2001, attacks. Also at stake are the sacrifices of the nearly 300 Marines killed in Afghanistan over the past three years.

Weighing against prolonging the conflict is its unsustainable cost and what author and former Defence Department official Bing West has called its "grinding inconclusiveness."

In a series of pep talks to Marines in Helmand this past week, Amos said the Marine mission in Afghanistan would end in the next 12 to 18 months.

That is as much as two years before the December 2014 deadline, announced a year ago, for all US and other foreign troops to leave the country.

"Savor being out here together," Amos told Marines on Thanksgiving at an outpost along the Helmand River called Fiddler's Green, "because it's going to be over" soon.

He was referring only to the Marines' role, which is limited mainly to Helmand, although there also are Marine special operations forces in western Afghanistan.