The Pentagon is working on plans for pulling out up to a third of the current 160,000 US troops in Iraq by the end of next year, barring any major new deterioration of security in the country.
The first withdrawals, of three of the 18 combat brigades stationed in Iraq, could come early in 2006, assuming the parliamentary elections set for December 15 go relatively smoothly.
Thereafter the speed of the pull-out would largely depend on whether newly trained Iraqi forces can shoulder a greater responsibility for maintaining stability.
The disclosure, in the Washington Post yesterday, is further confirmation that, despite President Bush's insistence that the US will 'stay the course' in Iraq, growing domestic opposition to the war is making a substantial force reduction all but inevitable.
Yesterday Condoleezza Rice, the Secretary of State, gave the clearest hint thus far.
US forces, she predicted were "unlikely to be needed in their present numbers for all that much longer." She was speaking as many other members of the US-led coalition, including Britain, Italy and most recently South Korea, are indicating that they intend to reduce their contingents in 2006.
There are roughly 22,000 non-US coalition troops in Iraq, 8,500 of them British.
The continuing presence of US forces has now become the central element in the bitter national debate over the war, especially after last week's call by John Murtha, the veteran Democratic congressman, former Marine, and military hawk, that US forces be withdrawn without delay.
Their presence had become part of the problem in Iraq, not part of the solution, an emotional Mr Murtha told the press.
Though he made clear he had a six-month time frame in mind, his plea stunned the White House, and provoked a storm on Capitol Hill.
Only a tiny anti-war fringe in Congress favours an immediate, unconditional US departure from Iraq, and a House resolution to that effect was defeated by 403-3.
But with the US death toll above 2,100 and discontent at Mr Bush's handling of the war increasing daily, Democrats and Republicans alike are leaving no doubt that something must be done, soon.
A key moment was last week's Senate resolution, passed by a bi-partisan 79-19 majority.
It rejected a fixed timetable for withdrawal, but demanded a fuller, regular accounting from the White House on how it intended to "complete the mission" in Iraq.
The Senators insisted that 2006 must be a year of "significant transition," when local Iraqi forces take the lead in ensuring security.
This should "create the conditions" for a phased "redeployment," i.e withdrawal, of US troops.
The critical moment may well be next month's parliamentary elections.
If these are successfully held, the US has a chance to declare victory and start to leave, arguing it has met its basic goal of replacing Saddam Hussein's regime with a united, sovereign Iraq with a democratically elected government.
Even then, the process will be gradual.
If past precedent holds, it could be several months before a new government is in place.
One idea gaining ground is to move some forces to Kuwait or offshore in the Gulf.
This might reduce resentment of the US as an occupying force, but still permit Washington to beef up ground forces in Iraq, if events took a turn for the worse.
But even that will require more Iraqi forces, in the words of Mr Bush, "to step up so that we can step down."The Pentagon says up to 210,000 Iraqis are being trained.
But critics say less than 1,000 are capable of operating on their own against insurgents, without some US help.