Such is the clincher as to why the torture tapes had to be destroyed. It wasn't just that Bush/Cheney et. al wanted to keep evidence of their torture program secret, there was never any complete way to do that. But there was only one thing that could prove they tortured for nothing and got nothing - the tapes. Cheney and his coterie of fellow Torquemadas were fiends proud of their handiwork; if they had evidence that it worked, they would have kept it. They burn spies for fun, crow on television about their willingness to torture and what they have accomplished, do you really think for one second they wouldn't retain proof if they had it?
And let us not forget just who we are talking about here - it is the White House Principals group:
The so-called Principals who participated in the meetings also approved the use of "combined" interrogation techniques -- using different techniques during interrogations, instead of using one method at a time -- on terrorist suspects who proved difficult to break, sources said.
Highly placed sources said a handful of top advisers signed off on how the CIA would interrogate top al Qaeda suspects -- whether they would be slapped, pushed, deprived of sleep or subjected to simulated drowning, called waterboarding.
The high-level discussions about these "enhanced interrogation techniques" were so detailed, these sources said, some of the interrogation sessions were almost choreographed -- down to the number of times CIA agents could use a specific tactic.
The advisers were members of the National Security Council's Principals Committee, a select group of senior officials who met frequently to advise President Bush on issues of national security policy.
At the time, the Principals Committee included Vice President Cheney, former National Security Advisor Condoleezza Rice, Defense Secretary Donald Rumsfeld and Secretary of State Colin Powell, as well as CIA Director George Tenet and Attorney General John Ashcroft.
As the national security adviser, Rice chaired the meetings, which took place in the White House Situation Room and were typically attended by most of the principals or their deputies.
Cheney, Rice, Rumsfeld, Powell, Tenet and Ashcroft. Means, motive and opportunity. Who could have imagined?
This certainly explains why it was top White House lawyers including Gonzales, Addington, Bellinger and Miers, with "vigorous sentiment", assisted the CIA in the decision and process to destroy the torture tapes of abu-Zubaydah and others.
(Every time I am reminded of that principles group watching "choreographed" torture before signing off on it, I am shocked and appalled all over again. )
As to the question at hand, considering the fact that Cheney and Rummy spent their entire careers trying to correct what they considered the sins of the Nixon administration, Bmaz's speculation makes sense. After all, they believed that Nixon's catastrophic error was failing to destroy the ... tapes.