A prominent opposition leader, Abdullah Abdullah, seated right, registers his candidacy in next year's presidential election in Kabul, Afghanistan, Tuesday, Oct. 1, 2013. The presidential election is a key vote that will help determine the success or failure of 12 years of U.S.-led military and political intervention in the country. (AP Photo/Rahmat Gul)

Photo by: Rahmat Gul

A prominent opposition leader, Abdullah Abdullah, seated right, registers his candidacy in next year's presidential election in Kabul, Afghanistan, Tuesday, Oct. 1, 2013. The presidential election is a key vote that will help determine the success or failure of 12 years of U.S.-led military and political intervention in the country. (AP Photo/Rahmat Gul)