The Afghan President Hamid Karzai's decision to call for national elections to be brought forward by four months has created huge security problems for American and British military commanders over sending reinforcements to safeguard the polls.
Although US President Barack Obama has ordered the dispatch of 17,000 troops, with numbers due to rise to 30,000, many of them will not be in place if Mr Karzai gets his way in holding the snap poll next month, at the height of the traditional Afghan fighting season.
Britain, which was expected to send up to 3,000 extra troops, faces even greater problems with the deployment largely dependent on the pullout from Iraq which is not due to get under way until May.
A brigade which had been prepared to be the next contingent in Iraq – but is now not expected to be needed – has been earmarked to be switched to Afghanistan in time for the original date of the elections, 20 August.
Senior officers, however, are wary of rushing the brigade to Afghanistan, in effect leaving no reserve force if things begin to unravel in Iraq. According to diplomatic and defence sources, Gordon Brown was due to offer an increase in non-military assistance to Afghanistan during his visit to meet Mr Obama in Washington, with the announcement of extra troops to follow at a later date. One reason for this was that an early declaration of British deployment would have taken the pressure off other Nato countries which both the US and the UK want to contribute much more to the conflict.
Mr Brown, say the sources, may yet decide to offer to send more British troops to shore up the special relationship with Mr Obama. That, however, will pose massive problems for the military.
The call for an early election, contained in a decree issued on Saturday, is widely seen as political brinkmanship by Mr Karzai, reflecting his growing frustration at waning Western support.
A US embassy spokesman stressed the need for an "orderly" election process to "maintain political stability". Senior British diplomats have described the situation as "very serious". Others warn that Afghanistan's fragile democracy might unravel.
Afghanistan's constitution states that presidential elections should take place 30 to 60 days before 22 May, when the incumbent's term ends. But the Independent Election Commission (IEC) chose 20 August, on the grounds that much of the country is still impassable in spring, because of snow, while other parts suffer a seasonal spike in violence.
Nonetheless, the 20 August poll, announced in January, left Mr Karzai open to claims that he did not have a legitimate right to power. Opposition groups had demanded he step down in favour of a caretaker government, but confusion reigned over who would take the helm.