Obama in Afghanistan

President Barack Obama steps off Air Force One during an unannounced visit to Bagram Air Base in Afghanistan. Friday, Dec. 3, 2010.

President Barack Obama is greeted by NATO Commander in Afghanistan Gen. David Petraeus, left, and U.S. Ambassador to Afghanistan Karl W. Eikenberry, center, after stepping off Air Force One during an unannounced visit to Bagram Air Field in Afghanistan, Friday, Dec. 3, 2010.

President Barack Obama is greeted by NATO Commander in Afghanistan Gen. David Petraeus, left, and U.S. Ambassador to Afghanistan Karl W. Eikenberry, after stepping off Air Force One during an unannounced visit to Bagram Air Base in Afghanistan, Friday, Dec. 3, 2010.

Soldiers from the 101st Airbourne await President Barack Obama's arrival for an unscheduled visit to Bagram Air Base in Afghanistan on Dec. 3, 2010.

President Barack Obama waves as he is introduced to the troops at a rally during an unannounced visit at Bagram Air Field in Afghanistan, Friday, Dec. 3, 2010.

President Barack Obama is introduced to the troops by NATO Commander in Afghanistan Gen David Petraeus at a rally during an unannounced visit at Bagram Air Field in Afghanistan, Friday, Dec. 3, 2010.

Afghanistan enters height of fighting season — AP Photo/Pablo Martinez Monsivais

President Barack Obama speaks to the troops at a rally during an unannounced visit at Bagram Air Field in Afghanistan, Friday, Dec. 3, 2010.

President Barack Obama greets troops at a rally during an unannounced visit at Bagram Air Field in Afghanistan, Friday, Dec. 3, 2010.