Gergen, who advised four presidents and is now editor-at-large of U.S. News and World Report,
"We've got this confluence now, people are calling it 'the imperfect storm.'
"You've got potential indictments this week. You've got pressure building up among conservatives for Harriet Miers to withdraw (as a nominee for the Supreme Court), and you've got the death toll in Iraq, sadly, ready to go over the 2,000 mark.
"Those coming together, I think, put the White House in the darkest place it's been since this president took office and to me, it's going to be a long climb out of the hole. If he were to lose (top political strategist) Karl Rove, he'll lose his right arm, and it's really hard to climb out of a hole without your right arm."
Rove and Vice President Dick Cheney's chief of staff, I Lewis "Scooter" Libby, have been mentioned as possible targets of the investigation being conducted by Special Counsel Patrick Fitzgerald.
Gergen says a that Libby first heard the name of Valerie Plame, the former CIA operative, from Cheney himself, rather than from journalists, could mean more trouble for Libby than Cheney.