Isn't there a better term for failing to know something you should have?
Neither Dan Rather nor President Bush are idiots; they're not ignorant; in fact both of them have access to considerably better information than the rest of us.
Bush should have known the true story about the weapons, and would have, if he'd let the inspectors do their jobs. After all plenty of people at the time had expressed their doubts that Saddam had any significant weapons capability.
Rather should have known the true story about the documents, and would have, if CBS hadn't totally dismissed the experts who were telling them that.
So they both have plausible deniability. Whoopty-do. I'm sure in both cases that was planned - "let's run with this, even though there's a lot of doubt; we'll just be sure we can claim to have been 'misled' at the time." In both cases its an abdication of responsibility - Rather's to inform truthfully, and Bush's to lead truthfully.