President Karzai suffered a humiliating blow to his authority yesterday after parliament rejected two-thirds of his nominees for a new cabinet, including the only woman and a warlord accused of human rights abuses.
The head of the United Nations in Kabul warned that Afghanistan risked floundering "without a functioning government", after just seven of the president's 24 ministerial candidates were approved in a secret ballot.
"It prolongs the situation without a functioning government, and that's a situation that has lasted since the election period [in August]," said Kai Eide, the Norwegian head of the UN mission in Kabul. "I think most of us were surprised by how many ministers were not approved."
Western officials said parliament was "baring its teeth" after eight years of being ignored by the President.
Mr Karzai's choice of cabinet ministers was seen as a key test of his resolve to root out corruption and cronyism, which has paralysed Western efforts to rebuild the country.
His nominees were a complex compromise aimed at appeasing the warlords, the international community and the hundreds of people to whom he promised jobs in exchange for their support in August's fraudulent presidential elections.
When the list of 24 names was announced two weeks ago, a month after he was sworn in as President and more than six weeks after he was declared the winner of the elections, it was largely welcomed by Kabul's western backers.
Many insist their aid money is dependent on Mr Karzai's pledge to clean up his administration.
Parliament's decision has left diplomats anxious the President may renege on pledge to reform, in order to get his cabinet approved.
In the past, when parliament passed a vote of no-confidence in his Foreign Minister, he simply ignored them.
"Karzai has often bypassed parliament, ignored parliament and kept his distance from parliament," a long-serving Western diplomat said.
"He's been slapping them in the face, and now they are baring their teeth."
Crucially, though, his choices of ministers for interior, defence, finance and agriculture were all approved. Between them, they are in charge of building up Afghanistan's security forces and boosting the economy, which is central to America's counter-insurgency strategy.
With MPs due to start a six-week winter recess soon, Mr Eide said it was unlikely that the President would get his cabinet in place in time for a major international conference on Afghanistan, due to take place in London on January 28.
"It will take weeks," Mr Eide said. "It could take more than weeks."
It is not yet clear whether the nominees will stay on as acting ministers until their replacements are approved, or whether their deputies will take over.
"It's for the Afghan government to resolve," said a Western diplomat. "We will continue to engage with whoever remains in place."
Mr Eide said that the only positive thing to come out of parliament's almost total boycott was that "it proves the institutions work".
He added: "Parliament has made full use of its authority under the constitution and that must be respected. We've seen it's not a rubber-stamping parliament, which we see in quite a lot of other countries."
The President's spokesman, Waheed Omar, admitted: "This is obviously not good in terms of the functioning of the government, in terms of services."
But he insisted that the ministries would continue to operate.
"This is the beauty of democracy," he said. "We are exercising democracy."