We know this to be true
I am 100% certain that Rumsfeld means what he says here. This war has never been about "blood for oil," or an American colonial imperative. The challenge will be how long will it take and at what cost to the American people to leave Iraq intact with a secular democratic government? My guess is at least five years.
This is a nation of 22 million people, 60% of whom are islamic fundamentalists who would prefer that we leave sooner than later so they can establish their islamic state. Its going to take more than Mr. Rumsfeld's words to keep these people patient.