On a farewell visit thanking troops in Afghanistan before his end of the month retirement, Defense Secretary Robert Gates warned against a bigger than expected troop withdraw next month.
"We still got a ways to go and I just, I think we shouldn't let up on the gas too much, at least for the next few months."
Aides say the President's not deciding to change his policy, just fine tuning a decision he's already made.
White House Press Secretary Jay Carney says:
"We're now at a point as envisioned by the President's policy where we can begin a draw down, the pace and scope of which will depend on conditions on the ground but it will begin."
Those conditions include how much the Taliban's been degraded and whether the Afghan troop training is on schedule.
Faster than expected troop training in Iraq allowed a faster than expected U.S. withdraw, but it's not going so well in Afghanistan according to Illinois Senator Mark Kirk.
"The Afghans are about 3 years behind the Iraqis. And I think I think Petraeus' recommendation is to start the major withdrawal in 2014 not 2012."
But current plans are for all foreign troops to be out by the end of 2014, and General David Petraeus, the U.S. Commander in Afghanistan, is one of several key officials who are changing roles, moving to head the CIA.
While current Director Leon Panetta, who favors fewer troops on the ground and more focus on drone strikes, becomes secretary of Defense.
Monday, President Obama held what may be the last monthly meeting of his Afghanistan and Pakistan Security Team before the decision is announced.
Brookings' Michael O'Hanlon believes we'll only see modest withdraws this year and most of next.
"I think that the draw down really accelerate roughly in the fall of 2012 because that's the end of the next fighting season. And we're gonna need two more fighting seasons to really consolidate gains in the south of Afghanistan first and then next the east of the country."
O'Hanlon says speeding the withdraw wouldn't save a significant amount of money and the President's Afghan surge, in the face of public opposition, showed a commitment he's unlikely to back away from.
"The president would have to change his own strategy in order to do anything more ambitious. Doesn't mean he wont, but the money's against it."
Officials say Bin Laden's death and the soaring war cost could strengthen the resolve of some of the president's advisors, who do want to bring troops home faster, including Vice President Biden.
But, President Obama has overruled them in the past.