With the signing of this deal, the US is now committed to assisting the Afghans with their security for the next decade.

New York Times:

The agreement - sweeping by design, with few details to bog down negotiators - puts down in writing for the first time the nature of the relationship the United States will have with Afghanistan once the bulk of American troops go home. It is meant to reassure the Afghan people that the United States will not abandon them, to warn the Taliban not to assume that they can wait out the West, and to send a message to Pakistan, which American officials believe has been hedging its bets in the belief that an American departure would leave the Taliban in charge.

"This is the proof in the pudding that we intend to be there," one United States official said Sunday, speaking on the condition of anonymity because he was not authorized to speak publicly.

The agreement came despite a series of setbacks in Afghan-American relations, including the burning of Korans, the massacre of 16 civilians attributed to a lone Army sergeant, and the appearance of grisly photos of American soldiers posing with the body parts of Afghan insurgents.

"In the midst of all these meteor strikes, we were able to still sit down across the table and get these documents agreed to," one NATO official noted. Many Afghans, including some who are ambivalent about the American presence, believe that the country's survival is tied to having such an agreement with Washington. They say it will make clear to the Taliban and to regional powers that the Americans will not walk away the way they did in the 1990s after the Soviets were pushed out of the country.

This may end very badly, I'm afraid. Few analysts are convinced that the Afghan army will be capable of handling security when the last NATO combat troops leave in 2014. They are getting better, though, and if some kind of power sharing deal can be struck between most of the Taliban and the Karzai government, some kind of security for the Afghan people might be realized.

But it's a long hard slog to negotiate with those elements of the Taliban willing to sit down with the government in Kabul. And those factions that refuse will make trouble for years to come. But there's no going back now - Karzai and his government will have to step up and take responsibility for their own future.