Hopes that the US can fix conditions for a long-term military presence inAfghanistan before an unofficial May deadline are fading because Hamid Karzai, the Afghan president, is not prepared to compromise on two demands that have stalled negotiations for months.
Washington and its allies want to have the US-Afghan strategic partnership agreed before May, when a Nato conference in Chicago is expected to pledge long-term help to Kabul with finances and military training.
But negotiations have dragged on for over a year and Karzai is adamant he will not give ground on his two main demands – for Afghan control of jails and an end to night-time raids on Afghan homes.
Western officials say the first is not practical and the second would compromise the military effort.
"If they don't change their position there will be no strategic partnership before Chicago," said a senior Afghan official familiar with the negotiations. "We are not willing to compromise when it comes to sovereignty."
The strategic partnership deal would allow US forces to stay in some current large bases in Afghanistan, to help train Afghan soldiers and police. The bases could also be used for drone strikes on militant areas in Pakistan.
The deal would give western leaders a security rationale for spending money in Afghanistan after combat troops are withdrawn in 2014, and also aims to reassure Afghans the west will not cut and run.
A string of top diplomats and politicians have urged Karzai to sign.
"The Afghan government, especially the Afghan president, is under a lot of pressure from all sides – there are some indirect threats being made as well," said the Afghan official, who asked not to be named because of the sensitivity of the negotiations.
But Karzai has long said that for a deal to go ahead the US must hand over all jails on Afghan soil to his government's control and end controversial night-time hunts for insurgents and their supporters.
He repeated that position in a phone call earlier this week with the Nato secretary general, Anders Fogh Rasmussen, who was urging Karzai to sign the deal ahead of the Chicago summit, according to the presidential palace.
"Before the US-Afghan strategic partnership document can be signed, the foreigners have to respect the national sovereignty of Afghanistan," a palace statement, released late on Wednesday, quoted Karzai telling Rasmussen.
"No Afghan [prisoners] should be in the hands of foreigners, and foreign troops should hand over all the jails they have now to the Afghan government, and stop the night raids."
US officials had suggested resolving the impasse by hiving off the two most controversial points into a separate document and agreeing to hash them out later, but Karzai has rejected that as a compromise of Afghan sovereignty.
"The US idea is not accepted at all, we have to reach an agreement on these two points before signing any strategic partnership document," the official said.
The US is reluctant to hand over jails in part because Afghanistan's judicial system does not currently have the capacity to run them.
Night raids are contentious because western military commanders consider them perhaps the most effective tool in their arsenal, saying they take out senior leaders with minimal risk to innocent civilians.
Afghan leaders say they are dangerous and intrusive, cause too many deaths of non-combatants and turn Afghans against the war.
Diplomatic manoeuvres that put Afghans officially in charge of prisons while leaving US forces organising day-to-day management, or gave US troops a role providing intelligence and support to Afghan-led night raids, could resolve some of the difficulties.
But western diplomats warn that Karzai may be badly misjudging the mood in an economically battered America, whose diplomats are also distracted by security concerns in other volatile areas from Syria and Yemen to Somalia.
"The Afghans still really believe that the Americans need to be here," said one senior Kabul diplomat who asked not to be named.
"I think they are underestimating how much things have changed, and US concerns are focused elsewhere – and they cannot manage without this support."
The World Bank forecasts Kabul will have a $7bn (£4.4bn) hole in its annual budget after 2014.
Mining projects may one day allow it to be self-sufficient, but they are in the very early stages of development, so foreign cash will be needed for years to pay the army.
While several other nations have signed their own long-term strategic deals – Britain has promised an officer training academy modelled on Sandhurst – all of them are unofficially contingent on a US deal; without an American lead, no one wants to stay.
The US embassy insists that there is no timeline for a deal, although repeated unofficial deadlines have passed without anything being pinned down.
"We are not going to comment on ongoing negotiations," said Gavin Sundwall, spokesman for the US embassy in Kabul.
"We want to get the right agreement, not necessarily a quick agreement, so there are no timelines."