"A leopard can't change it's spots."   "You can lead a horse to water but you can't make it drink."

Before he gave  his acceptance speech,  Don Trump  was told "all you have to do  to beat that unpopular Hilary  Clinton is act presidential, be calm , thoughtful and rational."  But he just couldn't do it. 
 Before she gave hers, Hilary was told  "all you have to do to beat that unpopular Trump is show your warm  human side, be modest, sincere  and open."  But she just couldn't do it. 

 The result, as David Brooks opined, were "the two worst speeches of the conventions."

While Dave McKee has a good idea in "run the veep" I'm afraid "what you see is what you got."