In many respects, the concept follows the precedent set in Iraq, where a similar troop surge and strategy shift under President George W. Bush in 2007 enabled American-led coalition forces to eventually hand over security duties to the Iraqis region by region. By last summer, Mr. Obama was able to pull out two-thirds of United States forces from Iraq and declare America’s combat mission there over.

“Iraq is a pretty decent blueprint for how to transition in Afghanistan,” one American official said Sunday, insisting like others on anonymity to discuss the strategy before its presentation. “But the key will be constructing an Afghan force that is truly capable of taking the lead.”…

Even after Afghan forces have assumed the lead in a province, some American or NATO forces may remain or be positioned “over the horizon” elsewhere in Afghanistan ready to respond quickly if necessary. By the end of 2014, American and NATO combat forces could be withdrawn if conditions warrant, although tens of thousands very likely will remain for training, mentoring and other assistance, just as 50,000 American troops are still in Iraq.

The plan came amid escalating pressure from President Hamid Karzai of Afghanistan to reduce the visibility of American troops, to halt night raids unless carried out by Afghan soldiers or police officers and to begin withdrawing foreign forces by next year.