The White House has issued its strongest warning yet that President Karzai cannot count on continued US support if he fails to accept that Afghanistan’s fraudulent election has critically undermined his authority.

President Obama was said yesterday to be more concerned at “whether there’s an Afghan partner” worth defending than with the politically fraught question of how many more troops to send, according to Rahm Emanuel, Mr Obama’s chief of staff and a central figure in White House deliberations on Afghanistan.

His rare public remarks were echoed by comments from Senator John Kerry, who has flown to Kabul to join efforts to persuade Mr Karzai to either accept a second round of voting or enter a power-sharing deal with his opponent, Dr Abdullah Abdullah.

The Karzai campaign has said it will not negotiate unless the incumbent is declared the outright winner of the August election. It raised the stakes further at the weekend by continuing to defy the UN-backed Electoral Complaints Commission.

The commission has spent more than eight weeks examining 2,584 allegations of ballot-stuffing, phantom polling stations and police intimidation. Its findings are expected to cut the President’s lead to about 47 per cent when made public this week — a figure that would require a run-off.

Mr Emanuel and Mr Kerry are considered doves in the debate on whether to grant General Stanley McChrystal’s request for up to 40,000 more troops. But their comments reflect growing White House frustration over Mr Karzai’s refusal to compromise, despite the events of August.

“It would be reckless to make a decision on US troop levels if you haven’t done a thorough analysis of whether there’s an Afghan partner ready to fill the space that US troops would create,” Mr Emanuel told CNN.

Using similar language, Mr Kerry said it would be “entirely irresponsible for the President of the US to commit more troops” before the electoral process had run its course and “we know who the President is, and what kind of government we’re working with”.

Mr Kerry said that he believed official claims that a second vote could be arranged within two weeks, but the Afghan winter is looming. In a worst case scenario, a run-off vote could stall efforts to introduce a new American strategy until spring.

The French Foreign Minister, Bernard Kouchner, led diplomatic efforts in Kabul yesterday, meeting Mr Karzai and Dr Abdullah. He said they both expressed “a real will to work together”. Scenarios discussed include a run-off before winter, a run-off in spring, or “Abdullah not competing in the run-off”.

Aides to Dr Abdullah said that working with a “corrupt” Karzai government would be “like drinking dirty water” — potentially fatal. But rhetoric on both sides has softened with the arrival of Zalmay Khalilzad, a former US ambassador to the UN, with a mission to bring the sides together.

Dr Abdullah has hinted that he will talk to Mr Karzai once results are announced, while diplomats say delegations from both sides have been meeting in secret over the past week.

The UK, US and UN have all urged Mr Karzai to seek a quick and peaceful resolution.

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