“These sources said the president responded to McCain by promising that the withdrawal would be based on conditions on the ground.”
Obama can’t have it both ways — if he is going to base withdrawal on conditions on the ground, then how can he announce the start of withdrawal in 2011, nobody knows what the conditions on the ground will be at the time.
By announcing a withdrawal date, Obama is sending a message to the Taliban and the terrorists, that all they have to do is just hang in there for another year and a half or so.