As Andrew Sullivan notes, the evidence that the reason Cheney pushed for torture (aka: harsh interrogation techniques) was because he wanted to make the case for war against Iraq even after the invasion of Iraq.
One other thing to consider - Cheney didn't come up with this fantasy alone. His good buddy, Ahmed Chalabi, was pushing the story years before Bush/Cheney got elected and years before 9/11.
Nevertheless, instead of admitting a mistake, the prince of darkness is continuing to spend an inordinate amount of time trying to justify the unjustifiable. And rather than preserving the legacy he imagines, he is being shown as accountable and responsible for the legacy we see he owns.
Funny how the media doesn't keep going back to Chalabi to let him make the case posthumously.