A Hard Deadline For Success in Afghanistan?

My excitment jumped seeing this Yahoo headline: Pentagon: Next 18 months key to Afghan victory

What does it mean?

He and Joint Chiefs Chairman Mike Mullen told senators they're more optimistic now than in recent months about efforts to combat insurgents and extremists along the remote Afghan-Pakistan border.

But, Mullen said, "I think the next 12 to 18 months will really tell the tale."

Gates emphasized that he did not mean the Afghan campaign would achieve success in that time, but rather that officials hoped to "see a shift in the momentum" by then.

"It's very important for us to be able to show the American people that we are moving forward ... to show some shift in momentum," Gates said. "This is a long-term commitment, but I believe the American people will be willing to sustain this endeavor if they believe this is not just a stalemate."

Oh. I see. So by 2011 we can at best expect a momentum shift. (Whatever that means.) At that time the war will be a decade old. If that's not a stalemate, I don't know what is.