Some fear a return to the dark days of the late 1990s, when the Taliban ruled most of Afghanistan with a centuries-old, unbending Salafi Islamist worldview. Others fear a breakdown of central government and return of warlordism, competing militias, and civil war.
A number of analysts, however, say Afghanistan has come too far since 2001 to disintegrate again into past eras of violence and lawlessness, and that those who fought over Kabul in the 1990s today have vested interests in keeping the peace in the capital.
"It's not important for us, the physical presence of Americans in Afghanistan, the numbers beyond 2014," says Hilaluddin Hilal, an Afghan Air Force general and deputy Interior minister for security until 2005.
"The important thing is a strong partnership and the existence of the US as an ally. We don't want the Americans to take part in the frontline fight against insurgents; we have enough [troops]," says Hilal.