The difference between stubbornness and tenacity is direction. If a leader is going in a foolish or destructive direction, he or she is being stubborn. If a leader is going in a positive and constructive direction, then he or she is being tenacious.
I believe John McCain is more motivated by humble and tenacious thinking and motives. Hillary Clinton and Barack Obama, in my opinion, are more motivated by stubbornness and ego.I feel much better about McCain's leadership of America for the next four years than the alternatives.