From a purely military perspective, announcing a timeline makes no sense. It gives our adversaries insight into our plans, dulling the edge of strategic ambiguity. But changing the trajectory of this war requires much more than killing and capturing Qaeda and Taliban fighters.
But the administration's perspective isn't "purely military." Thank goodness! This isn't about America looking "manly" -- standing on an aircraft carrier in front of waving flags and saluting military. This is about America achieving a crucial and respected political objective.
Progress depends on two political developments: inducing the administration of President Hamid Karzai to govern effectively, and persuading Pakistan that militant groups within its borders pose as great a threat to Islamabad as they do to Kabul. A limit to America’s commitment may actually help us meet these goals. (The Democratic victories in the 2006 midterm elections, for example, convinced Iraqi Sunni leaders that the United States was on its way out, inspiring them to join the Awakening movement that led to better security across the country.) The strategic benefits of setting a timeline, in this case, may outweigh its tactical costs.
Whether these political objectives are met will be the best measure of the effectiveness of the administration’s plan. ...Nathaniel Fick, New York Times