Fred Kaplan homes in on the central point of contention, and confusion, in Obama's speech - the July 2011 date:
Critics say that this sends the wrong signal to the Afghan people; that if they think we're leaving in less than two years, they won't trust us to protect them in the first place; and that, in any case, the Taliban will simply lie low and "wait us out." This complaint misreads the policy. The key word in Obama's speech was that in July 2011, the United States will "begin" to transfer responsibility for security to the Afghan forces. The pace of this transferhow quickly we will continue to withdraw and at what point we'll get out altogetherwill be determined by "conditions on the ground." (Obama may not have underscored this phrase, but in a background press briefing earlier in the day, "senior officials" emphasized it strongly; one predicted that it would be the most misunderstood and misreported part of the speech.)