For years, US officials have pointed to the improvements in the everyday lives of Afghans made possible by billions of dollars in aid from the US and elsewhere.
In Afghanistan, people now live 20 years longer on average than under Taliban rule, they say; seven million more children attend school and women are 80 per cent less likely to die in childbirth.
The spectre of an abrupt departure of all US and Nato soldiers from Afghanistan at the end of next year now imperils these gains, they warn, and endangers progress on the massive development challenges that remain.
Unless the Obama administration can persuade Afghan President Hamid Karzai to sign a security pact that would permit a modest US force to remain beyond 2014, the US is almost certain to drastically scale back aid to Afghanistan.
That would force aid groups to work under more precarious security conditions and compete for scantier aid dollars.
It would be “a complete catastrophe” to pull the entire US force from Afghanistan next year, said Andrew Wilder, who directs Afghanistan and Pakistan programmes at the US Institute of Peace and spent years working in the region.
A deterioration in security conditions would hamper oversight of aid projects, possibly making a deeply sceptical Congress even more reluctant to fund Afghan aid.
A smaller staff at the US embassy in Kabul would also make it more difficult to sustain many US aid programmes.
“My judgement is no troops, no aid, or almost no aid,” James Dobbins, the US envoy for Afghanistan and Pakistan, told Congress this month.
“The political support for the aid comes from the military presence.”
Last year, the US and other donors promised to provide Afghanistan $16 billion in aid through 2015, at least half of which must go through Afghan government coffers. Afghanistan’s government also promised to work towards benchmarks in governance, human rights and fighting corruption.
Since the Taliban government was ousted in 2001, the US has already spent at least $88 billion on Afghan aid, not including the much larger bill for combat costs.
After arduous negotiations on the US-Afghan security agreement were completed last month, Washington expected Karzai to sign it, paving the way for a force of possibly around 8,000-12,000 US and Nato troops to remain after 2014. There are about 39,000 US soldiers in Afghanistan now.
Instead, Karzai has refused to do so, suggesting the pact should be signed following Afghan presidential elections in the spring. The Obama administration says that would not leave Washington and its allies enough time to plan for a possible post-2014 mission.