From The Top 10 Conservative Idiots (No. 225), democraticunderground.com

Donald Rumsfeld
On PBS' Newshour last week, Defense Secretary Donald Rumsfeld said the following:

I was very careful. I never predicted any number of deaths or the cost or the length because I've looked at a lot of wars, and anyone who tries to do that is going to find themselves wrong, flat wrong ... I don't know anybody who had any reasonable expectations about the number or the length of the war or the cost of the war. I just don't - no one I know went out and said these are how those three metrics ought to be considered. And you can take it to the bank.

Okay, where to begin... well, first it's probably worth noting, as Atrios did last week, that a Defense Secretary who wants to start a war but hasn't got any idea whatsoever of the potential length, the potential cost, or the potential number of casualties, probably shouldn't be doing the job of Defense Secretary. Atrios didn't put it quite as politely as that, mind you.
And second, it turns out that Rumsfeld and other administration officials have made predictions about the "three metrics" - it's just that they all turned out to be wrong. Flat wrong, if you will. From Think Progress:

Length:

Rumsfeld, 2/7/03: "It could last six days, six weeks.
I doubt six months."
Cheney, 3/16/03: "I think it will go relatively quickly, . . . (in) weeks rather than months"
Cost:
Daniels, 12/30/02: "The administration's top budget official [Mitch Daniels] estimated today that the cost of a war with Iraq could be in the range of $50 billion to $60 billion... Mr. Daniels declined to explain how budget officials had reached the $50 billion to $60 billion range for war costs..." [New York Times, 12/31/02]

Casualties:
Q: If your analysis is not correct, and we're not treated as liberators, but as conquerors, and the Iraqis begin to resist, particularly in Baghdad, do you think the American people are prepared for a long, costly, and bloody battle with significant American casualties?
Cheney: Well, I don't think it's likely to unfold that way, Tim, because I really do believe that we will be greeted as liberators. [Meet the Press, 3/16/03]

So to sum up, Don Rumsfeld isn't just incompetent, he's a liar.

And you can take that to the bank.