"I suggested that we were losing the war," Adelman, a long-time friend of Rumsfeld, told The New Yorker in an interview posted online on Saturday.
"What was astonishing to me was the number of Iraqi professional people who were leaving the country. People were voting with their feet, and I said that it looked like we needed a Plan B. I said, 'What's the alternative? Because what we're doing now is just losing.'"
He said Rumsfeld did not take the assessment well.
"He was in deep denial -- deep, deep denial. And then he did a strange thing. He did 15 or 20 minutes of posing questions to himself, and then answering them. He made the statement that we can only lose the war in America, that we can't lose it in Iraq. And I tried to interrupt this interrogatory soliloquy to say, 'Yes, we are actually losing the war in Iraq.' He got upset and cut me off. He said, 'Excuse me,' and went right on with it."
Adelman's prognosis of the situation in Iraq was a major departure from his now-famous 2002 prediction that invading the country would be a "cakewalk."
And it angered Rumsfeld, who complained that Adelman had become "disruptive and negative."
Adelman told The New Yorker that he replied: "'I'm negative about two things: the deflection of responsibility, and the quality of decisions.' He (Rumsfeld) said he took responsibility all the time. Then I talked about two decisions: the way he handled the looting" after the invasion of Iraq, and the Abu Ghraib prison scandal.
"He told me that he didn't remember saying, 'Stuff happens'" with regard to the looting, Adelman said.
"He was really in denial that this was his fault," Adelman said, adding that it occurred to him at that time that Rumsfeld might really think that "things are going well in Iraq."
A short time before the election, Rumsfeld informed Adelman that his office would be seeking a replacement for him on the Defence Policy Board, a group of lobbyists, defence experts and former politicians who advise the secretary on strategy and management issues, according to The New Yorker.
Adelman told the magazine that the Iraq war "made me doubt the past. Was I wrong all those years, or was he just better back then? The Donald Rumsfeld of today is not the Donald Rumsfeld I knew, but maybe I was wrong about the old Donald Rumsfeld. It's a terrible way to end a career."
Adelman had told Vanity Fair magazine in an interview just before the November 7 legislative elections that President George W. Bush's national security team "turned out to be among the most incompetent teams in the post-war era."
Rumsfeld resigned on Wednesday, in the wake of the congressional elections which saw Republicans lose control of both houses of the US Congress.
Though Rumsfeld had offered his resignation to the president twice, before and after the prisoner abuse scandal at Abu Ghraib in Iraq, Bush stood by him up to the elections, even as calls for his resignation mounted, including among republicans.

Copyright AFP (Agence France-Presse), 2006