Nato is pinning its hopes on the Taliban settling for a role in the Afghan government but not leading it, despite warnings that the state could instead cease to function as a result of the group's continuing insurgency.
Nato's senior civilian representative in Kabul told a London panel that the best scenario after the Western Alliance withdraws this summer would be for the Taliban to be "part of the government, not as the government".
"I think that is the development that we all expect but it's up to the regional countries to make it happen," Stefano Pontecorvo told the Regional Powers and Post-Nato Afghanistan conference.
Leading analysts at the meeting said there was a real prospect of the Taliban seizing power within a year of western troops leaving.
There are also concerns that the exit of the 10,000 US and Nato forces could result in a bloodbath when next year's "fighting season" begins in early spring, turning the country into "Syria II".
A lack of consensus among the neighbouring governments – Pakistan, India, China, Russia and Iran – means that a power struggle is inevitable, the Royal United Services Institute (Rusi) online seminar heard.
But the deepest worry is that, as when Russia’s decade-long occupation ended in 1989, the Taliban will take control through force and impose its harsh theocratic regime on the population.
“The way things are going there may not be an Afghan state a year from now and there may be a Taliban autocracy, so I don't think there is an endless time we can wait for regional consensus to fall,” said Dr Antonio Giustozzi, a Taliban expert from the University of London.
The United Nations is now preparing for an increase in violence, the global body's refugee chief said. “The withdrawal of American troops from Afghanistan is another indicator that violence may rise after that,” Filippo Grandi told AFP. “We are making plans for it.”
The Taliban have made territorial gains across Afghanistan as peace talks with the Afghan government stalled. With the Nato and US troops withdrawing before September it is understood that the extremists are awaiting their exit before launching an offensive early next year.
The Kabul government is hoping that Afghan security forces will keep the Taliban at bay, with some help from remaining US and British special forces.
Key to Afghanistan's future will be the involvement and influence of its neighbours. Foremost is Pakistan, which has ties to the Taliban and leverage within the Afghan government, having largely pushed aside its traditional foe India.
"There does not need to be a so-called proxy war between India and Pakistan over Afghanistan," said Rahul Roy-Chaudhury of the International Institute for Strategic Studies think tank. "There are bad options for Pakistan as well."
He said that India would support a non-Taliban government with continued aid, and was against a civil war in Afghanistan “where there's Al Qaeda, anarchy and conflict, as this is very bad news for India”.
The Russians, who have been accused of paying bounties to the Taliban for dead American troops, have increased their influence "by reaching out to all the different players" from all sides, following their "playbook from the Middle East", said David Lewis of Exeter University.
“The Russians feel that they have enough there to have some influence over a future administration that the Taliban might be part of.”
He said that Moscow believed its regional diplomacy was “in a good place” and that Russia “now does want a stable Afghanistan”.
China, which had hoped to reap economic benefits from the country, is now more concerned about the conflict spilling over its border into the largely Muslim Xinjiang province.
“China doesn't really care as long as Afghanistan is not exporting its problems to them, that's where their concern lies,” said Rusi’s Raffaello Pantucci.
Iran, which currently has one million Afghan refugees, is another country with deep concerns over a Taliban takeover because the previous extremist regime ousted by the US in 2001 was “very problematic for it”, said Rusi’s Dr Aniseh Bassiri Tabrizi.
But Tehran has little control over events across its eastern border. "Iran has felt like it has very little leverage on what's going on and what could happen to the country [in future][," she said.
Ultimately, once the US has departed it will be down to the country's neighbours to ensure stability, said Mr Roy-Chaudhury. "My sense is that the region has to be part of the solution for Afghanistan, there is no other option. But the problem is that there is no regional consensus towards the future of Afghanistan."
The "most internationally legitimate" solution would be for the Doha peace talks "to somehow succeed", Dr Giustozzi said.
Without the reliance on foreign troops the Afghan government might be forced into power sharing with the Taliban, although that comes with dangers, Mr Pontecorvo said.
He said the West’s presence had effectively blocked the political process, or reforms from progressing. “The Nato forces were a good reason for nothing to happen. Now that good reason has gone. We made it clear that we are committed to Afghanistan but we have also a number of other competing priorities.”
Mr Pontecorvo said that Nato would continue to fund Afghanistan with $4 billion a year, at least until 2024.
The worse scenario would be an enduring civil war leading to another intervention, said the UN's Filippo Grandi. "The crisis can start again, which means that after a few years, more troops have to be sent back. This is our concern in Afghanistan for sure."