If CBS News were to come on the air tonight and announce that former Presidents Bill Clinton and George H. W. Bush had said things they never said — expressing contempt, say, for their wives or proposing war against Iran — it would take only minutes before everyone involved with the fiction was thrown out the door. They'd be gone as well if the evening news had taken a true event, say a president's dalliance with an intern, and lacking film or tape of their first meeting, hired actors to stage a hug on the White House lawn. Well, of...