Tenet:

"We all understood bin Laden's intent to strike the homeland but were unable to translate this knowledge into an effective defense of the country," Tenet said.
"This is not a clinical excuse," he said. "No matter how hard we worked or how desperately we tried, it was not enough."

This is the type of straight talk and obvious statement I speak of when I wonder why the President (any president) refuses such a statement. Why won't they say: we tried, but in the end, we failed in some way to protect Americans from terror. We hope the 9/11 Commission will assist in solving the problem.
Tenet and Clarke have said just that. This is not so much to bash the current administration --and honestly I have no idea what Clinton has or has not said to this effect. It is rather a confusion with the politics. More than anything, I'm simply mystified at why such remarks are supposedly damaging politically.