Two years for the mission in Afghanistan?

U.S. officials have long resisted putting a timeframe on the Afghanistan mission. Thus, it is noteworthy that today's Washington Post quotes an anonymous administration official suggesting the mission has "about two years" to succeed:

One senior government official involved in Afghanistan policy said McKiernan was overly cautious in creating U.S.-backed local militias, a tactic that Petraeus had employed when he was the top commander of U.S. forces in Iraq. "It's way too modest," the official said, speaking on the condition of anonymity. "We don't have 2009 to experiment in Wardak province," where one such militia has been set up. "I think we've got about two years in this mission. The trend lines better start swinging in our direction or we're going to lose the international community and we're going to lose Washington."

While the statement falls short of a public timeline, it suggests the administration believes it has a brief window to transform conditions in Afghanistan and the heightened troop levels cannot remain indefinitely. The February CSIS report on the subject, Afghanistan and Pakistan on the Brink: Framing U.S. Policy Options, recommended the U.S. and its allies should embrace a 3 year military commitment (drawing down in December 2011):

Secure a three-year military and economic commitment from the allies and signal to the Afghans that the military commitment is not open-ended, although the financial commitment will continue. The 134,000-soldier target strength of the Afghan National Army by December 2011 is consistent with this timeframe. Ensure that the elected governments of Pakistan and Afghanistan accept leadership responsibility (p. 4, 14-16).