PAKISTAN:PERVEZ MUSHARRAF'S resignation has left the United States fearful of a power vacuum in Pakistan and uncertain about the future of joint counter-terrorism operations along the border with Pakistan.
Washington made no effort to save Mr Musharraf, whom it regarded as weakened since he relinquished his military role last November and US officials dismissed moves to impeach him as an internal matter.
The Bush administration has good relations with Ashfaq Kayani, who succeeded Mr Musharraf as head of the army but its influence over Pakistan's civilian government is weakening. Washington is especially uneasy about the power of former prime minister Nawaz Sharif, who leads a junior partner in the coalition headed by the People's Party, which is led by Benazir Bhutto's widower, Asif Ali Zardari.
Mr Sharif is perceived in Washington as lacking in enthusiasm for the fight against the Taliban and al-Qaeda and US officials fear that infighting within Pakistan's government could undermine counter-terrorism co-operation.
The CIA recently confronted Pakistan with evidence that pointed to the involvement of the country's Directorate for Inter-Services Intelligence (ISI) in last month's bombing of the Indian embassy in Kabul.
The ISI has been reluctant to abandon its intelligence assets among militant groups on the Afghan border and within the Taliban, partly because it believes that Nato forces will leave Afghanistan sooner rather than later and is determined to prevent India playing a bigger role there.
The US blames terrorist safe havens in Pakistan's tribal regions for many of the attacks on Nato troops in Afghanistan and Washington is frustrated by what it sees as Pakistan's reluctance to pursue militants within its borders.
Pakistani military commanders complain that it is difficult to motivate soldiers to attack targets within Pakistan and Washington wants flexibility for US soldiers to pursue militants into Pakistan.
Democratic presidential candidate Barack Obama yesterday repeated his demand that US forces should be able to pursue Osama bin Laden into Pakistan even without Islamabad's permission. He added, however, that the US should triple non-military aid to Pakistan and forge a new relationship with its civilian government.
"I argued for years that we need to move from a 'Musharraf policy' to a 'Pakistan policy'," he said.