Indeed, you could almost hear the knees knocking in Karzai's embassy here when incoming Obama officials met privately during inauguration week with at least two Afghan politicians who would like to replace the president.
With the war going badly, criticism has grown of Karzai's seeming tolerance of endemic corruption in his government, which threatens to turn Afghanistan into a narco-state, if not grease the return of the Taliban to power.
Could his days be numbered?
If such discord sounds ominous, it may be because it's redolent of the acrimony between Washington and its South Vietnamese ally, Ngo Dinh Diem, amid another U.S.-backed counterinsurgency war in the summer of 1963. A few months later, a U.S.-backed cabal of generals overthrew - and murdered - him and his brother.
"There clearly is an increased tempo in the press commentary from government sources about general dissatisfaction about his performance," acknowledges a former practitioner of U.S. covert action.
Karzai and his circle also sense which way the wind is blowing, said an official familiar with their thinking.
"There are many, many political rumors swirling in Kabul right now," said this official. "There is plenty of jockeying taking place between people looking to challenge Karzai, and many of them have made overtures to the Obama administration."
It's well understood in Kabul, he added, that "some U.S. officials think that replacing an individual will somehow remedy Afghanistan's many problems. The troubles we see in Afghanistan today are the fault of both the Afghan government and its international partners, and no number of individuals - no matter how qualified - will be able to tackle them alone."
"Pushing him out," agreed the covert action veteran, who spoke only on condition of anonymity because he did not want to attract the attention of his former employer, "won't solve the corruption problem, and in fact may increase instability."
In any event, he added, "any new administration should not move quickly to promote regime change until they get their sea legs."
But journalist and author Peter Bergen cautioned that criticism of Karzai "is not new... dissatisfaction with Karzai has been going on a long time."
National elections, now scheduled for August, provides "a mechanism for him to disappear" if Washington grows completely disillusioned -- and has an alternative candidate, added Bergen, author of Holy War, Inc. and other books on Islamic fundamentalist terrorism.
But "let's say Washington decides to get rid of him," Bergen added, "Who fills his shoes?"
There's a handful of pretenders to the presidential office, he said, ticking off the names of former ministers in the Kabul government. But none have the national following of Karzai, scion of a prominent Pashtun tribe.
Any non-Pashtuns need not apply.
"You can't run the country if you're not a Pashtun," who amount to 40 per cent of the population, Bergen said.
Catapulting an ethnic minority into power would invite a "catastrophe," he predicted, far worse than the Iraq insurgency that grew out of Sunnis being displaced by the U.S. invasion and shut out of power by the Shiites.
For those and other reasons, "I don't think anyone's trying to push Karzai out," says Gary Berntsen, who led one of the first CIA teams into Afghanistan and rallied its tribes against the Taliban. He spent another year there during 2007-2008.
The CIA would "absolutely not" back a coup d'état, at least not under the present conditions, Berntsen said.
"A lot of Afghans still rally around him." ##