WHY NOT A SIMPLE "YES"?

Bob Schieffer asked Cheney if Pres. Fredo knew about torturing prisoners, a simple "yes-no" question, and Cheney couldn't answer simply. From Face the Nation, 5/10/2009:

SCHIEFFER: How much did President Bush know specifically about the methods that were being used? We know that you-- and you have said-- that you approved this...
CHENEY: Right.
SCHIEFFER: ... somewhere down the line. Did President Bush know everything you knew?
CHENEY: I certainly, yes, have every reason to believe he knew -- he knew a great deal about the program. He basically authorized it. I mean, this was a presidential-level decision. And the decision went to the president. He signed off on it.

In the past, Cheney's belief statements have turned out to be VERY wrong:

"He's had years to get good at it and we know he has been absolutely devoted to trying to acquire nuclear weapons. And we believe he has, in fact, reconstituted nuclear weapons."
Source: Meet the Press, NBC (3/16/2003).

"I continue to believe. I think there's overwhelming evidence that there was a connection between al-Qaeda and the Iraqi government. We've discovered since documents indicating that a guy named Abdul Rahman Yasin, who was a part of the team that attacked the World Trade Center in '93, when he arrived back in Iraq was put on the payroll and provided a house, safe harbor and sanctuary. That's public information now. So Saddam Hussein had an established track record of providing safe harbor and sanctuary for terrorists. . . . I mean, this is a guy who was an advocate and a supporter of terrorism whenever it suited his purpose, and I'm very confident that there was an established relationship there."
Source: Morning Edition, NPR (1/22/2004).