Mr Perle, a member of the influential Defence Policy Board that advised the defence secretary, Donald Rumsfeld, in the run-up to the war, is as outspoken in denouncing the conduct of the war as he was once bullish on the invasion. He blamed "dysfunction" in the Bush administration for the present quagmire.And what about the chap who said that the war on Iraq would be a "cakewalk?"
"The decisions did not get made that should have been. They didn't get made in a timely fashion, and the differences were argued out endlessly," Mr Perle told Vanity Fair, according to early excerpts of the article. "At the end of the day, you have to hold the president responsible."
Asked if he would still have pushed for war knowing what he knows now, Mr Perle, a leading hawk in the Reagan administration, said: "I think if I had been delphic, and had seen where we are today, and people had said, 'Should we go into Iraq?', I think now I probably would have said, 'No, let's consider other strategies for dealing with the thing that concerns us most, which is Saddam supplying weapons of mass destruction to terrorists'."
Kenneth Adelman, another Reagan era hawk who sat on the Defence Policy Board until last year, drew attention with a 2002 commentary in the Washington Post predicting that liberating Iraq would be a "cakewalk".Did you se that? "the idea of using our power for moral good in the world?" Leave aside the relentless aggression called for by this imperialistic idea. How does he square "moral good in the world" for the neo-cons' support for Israel?
He now says he hugely overestimated the abilities of the Bush team. "I just presumed that what I considered to be the most competent national security team since Truman was indeed going to be competent," Mr Adelman said.
"They turned out to be among the most incompetent teams in the postwar era. Not only did each of them, individually, have enormous flaws, but together they were deadly, dysfunctional."
He too takes back his public urging for military action, in light of the administration's performance. "I guess that's what I would have said: that Bush's arguments are absolutely right, but you know what, you just have to put them in the drawer marked 'can't do'. And that's very different from 'let's go'."
Mr Adelman, a senior Reagan adviser at cold war summits with Mikhail Gorbachev, expressed particular disappointment in Mr Rumsfeld, who he described as a particular friend. "I'm crushed by his performance," he said. "Did he change, or were we wrong in the past? Or is it that he was never really challenged before? I don't know. He certainly fooled me."
Mr Adelman said the guiding principle behind neoconservatism, "the idea of using our power for moral good in the world", had been killed off for a generation at least. After Iraq, he told Vanity Fair, "it's not going to sell".