Some of the leading contenders in Afghanistan's presidential election:
ABDULLAH ABDULLAH: Having gained 31 percent of the vote as runner-up to Hamid Karzai in the disputed 2009 elections, Abdullah has an advantage in name recognition and political organization. He was a close aide to the late Ahmad Shah Masood, the Northern Alliance rebel commander famed for his resistance to Soviet occupation and the Taliban. Abdullah has a strong following among ethnic Tajiks in Afghanistan's north, but his perceived weak support among Pashtuns — Afghanistan's largest ethnic group at 42 percent — could keep him from gaining a majority of votes, even though he is half-Pashtun.
ZALMAI RASSOUL: A former foreign minister, Rassoul has been national security adviser to the government and is seen as close to Karzai. He could end up being a consensus candidate among many political factions. A Pashtun like Karzai, he has a medical degree and is fluent in five languages, including French, English and Italian.
ASHRAF GHANI: Ghani is a former finance minister who ran in the 2009 presidential elections but received just 3 percent of the vote. A well-known academic with a reputation as a somewhat temperamental technocrat, Ghani chairs a commission in charge of transitioning responsibility for security from the U.S.-led coalition to Afghan forces.
ABDUL RAB RASOUL SAYYAF: An influential former lawmaker and religious scholar, Sayyaf is one of the more controversial candidates among Afghanistan's foreign allies because of his past as a warlord during the 1990s civil war and allegations of past links to radical jihadists including Osama bin Laden. As a Pashtun and charismatic speaker, he may appeal to Afghanistan's large numbers of religious conservatives.
ABDUL QAYYUM KARZAI: A businessman and the elder brother of President Karzai, he studied in the United States and previously served in the National Assembly. He is not seen as his brother's favored successor, and the Karzai name could be a double-edged sword, since many Afghans are frustrated with the current government's corruption.