Afghan politician Abdullah Abdullah, center, sits with his two vice-presidential candidates, Mohammed Mohaqiq, right, and Mohammad Khan during a registration process for the forthcoming presidential election. (Massoud Hossaini/AFP/Getty Images)

By Sunday evening, the list of candidates registered for next year’s presidential elections included some of Afghanistan’s most powerful officials and most notorious warlords.

In a country still wrestling with democracy 12 years after the Taliban was overthrown, the high-profile candidates represent the pluralism of modern Afghan politics as well as the power still wielded by informal strongmen who once tore Afghanistan apart.

The election comes at a crucial moment, as foreign troops prepare to withdraw by the end of 2014 and with U.S.-Afghan relations at a gridlock that could prevent a long-term security agreement from being signed. A well-run election and a qualified victor would help sustain the gains of the past 10 years, Western officials say. But with the stakes so high and the candidates so divisive, an electoral dispute could have devastating consequences.

More than two dozen presidential candidates — each with two ­vice-presidential running mates — are registered for the election, which is scheduled to take place in April. Among those running are President Hamid Karzai’s brother; a religious scholar accused of leading a bloody campaign against the Hazara minority ethnic group; one of the country’s most powerful and controversial provincial governors, nicknamed “the Bulldozer”; a former militia leader whom Human Rights Watch accused of “widespread looting and violence”; and an Uzbek leader widely accused of war crimes.

Also on the list are some of the technocrats who have ascended the ranks of Afghanistan’s government over the past decade: the country’s foreign minister, a World Bank official who became finance minister, a former defense minister who frequently lectured at Washington think tanks, and a sharply dressed ophthalmologist who became a vocal opposition leader after serving as a top diplomat.

In some cases, those who have led ministries and those who have led militias or shadowy patronage networks are running together.

Ashraf Ghani, the former World Bank official, chose Gen. Abdurrashid Dostum, the Uzbek warlord, as his running mate.

Abdullah Abdullah, the ophthalmologist and a former foreign minister, chose Mohammad Mohaqiq, the former militia leader.

Some chose running mates from different parts of the country but with similar positions in Afghan society. Abdurrab Rasul Sayyaf, the religious scholar turned mujahideen commander, chose Ismail Khan, who once commanded a large swath of western Afghanistan. Khan, suggesting that Afghan civilians take security into their own hands, told Der Spiegel last month: “What good is this army? It has only been provided with rifles.”

With so many candidates — and tickets comprising such odd bedfellows — it’s hard to discern a clear favorite. For now, Abdullah; Zalmay Rassoul, the current foreign minister, and Qayum Karzai, the president’s brother, are seen by many as the front-runners. Each will struggle to develop a broad voter base in a country still divided by ethnicity, tribe and geography. Rassoul is the only viable candidate with a female vice president on his ticket: Habiba Sorobi, governor of Bamyan province.

Whoever wins the election will inherit a position held by one man, Hamid Karzai, since the Taliban was overthrown in 2001. Karzai managed to mostly keep ethnic tensions at bay but failed to reach a peace agreement with insurgents or to build public confidence in the country’s nascent bureaucracy. The Taliban refused to take part in Afghan elections, despite Karzai’s entreaties.

Western aid helped codify improvements in education and human rights during Karzai’s presidency, but in many cases those gains never trickled down to rural Afghanistan, including places where the insurgency holds sway. Efforts to combat that insurgency are now spearheaded almost entirely by Afghan forces, which have shown ambition despite soaring casualty rates and a troubling lack of air support.

One by one, candidates arrived at the Independent Election Commission in Kabul, flanked by dozens of gunmen, pledging their ability and willingness to keep Afghanistan from descending further into strife. On Sunday, the final day to register campaigns, they struck a tone that Western officials would have approved of but made few specific promises.

“I hope to keep the gains of the last 10 years. I want to serve all Afghans,” Rassoul said after his supporters showered him with flowers.

“I’d like to have good relations with our neighbors and the international community on the basis of Afghan sovereignty,” said Qayum Karzai, whose campaign team said his brother had not officially endorsed him.

For months, many Afghans and Western officials have expressed concern that elections could be delayed as tribal leaders in southern Afghanistan have requested, citing security problems. Such a delay would be a blow to a democratic transition that Western officials consider a cornerstone of the country’s future. The international community is slated to deliver billions of dollars annually to Afghanistan, but Western officials have said that pledge hinges at least in part on timely and credible elections.

While those concerns linger in some circles, Hamid Karzai has repeatedly said that he plans to leave office next year. He also has suggested that his successor may be the one to sign a deal allowing an enduring American military presence here, alluding to the current stalemate. But U.S. officials have indicated that it might be too late for an agreement by then.

The last Afghan election, in 2009, was marred by allegations of voter fraud and concerns from Karzai about Western interference. Karzai defeated Abdullah in a runoff vote, but he never entirely forgave the United States for — as he saw it — conspiring to unseat him. He has vowed that the international community will have no role in next year’s elections, which will be planned and monitored by the country’s own Independent Election Commission.

Last month, as accused war criminals began expressing interest in running for president, some officials at the commission considered blocking their candidacy, citing their participation in past violence.

“They have blood on their hands,” one member of the commission said.

But as more candidates with questionable reputations announced their intention to run, the commission stood back.

Anyone not convicted by an Afghan court could run, the commissioners ruled.

“The voters will decide,” said the head of the commission, Ahmad Yousuf Nuristani.