Is Mc Cain speech his downfall? and is Bush IQ higher than Mc Cains? ?

I heard many presidential nominee speech's and this one is similar to to a town hall election speech, why isn't he talking of how we will regenerate the economy while engaging in two wars and with his proposition to decrease taxes. As for Bush he was more articulate and informative during his 2000 presidential campaign: now we know that he is a complete moron: is Mc Cain a similar case or even worse?