An honest man, a man of good principles, those in harmony with those reflected in our Declaration and Constitution, i.e. individual rights and limited government, a nation of laws, not of the whims of regulators and a power-lusting President, can speak off the cuff because there is nothing to hide or finesse or misrepresent.
A Pragmatist, someone with _no_ principles but what works in the range of the moment, for example, Joe Biden, can speak off the cuff, because homilies, slogans, and jokes are all he’s got and suitable for all occasions.
A dishonest man, a man of rotten principles, those which are antinomic to our own, must lie constantly and very carefully, if he is to mask his agenda, and speaking off the cuff is a minefield that he can only pick his way across with great care and not for long. And the evil are most often the intellectually sloppy and lazy, so Obama says the most damning things when he and his handlers are not paying attention and “on message.”