As for McCain I questioned that and after going around reading on it it was easy enough to see that for some reason citizenship laws were passed to cover the situation. End of Argument for McCain. The difference would be a win by McCain, if he won do you think there would still be fuss over legality since it is clear the citzenship laws cover him, no probably not except for a lunatic fringe. But if McCain were a Mestizo, you better believe there would be, that socially base problem in the birth argument does not lay exclusively with Republicans.
We must remember the Constitution has that clause in as a protection against monarchies from establishing power bases in the USA and to prevent the USA from foreign rule in general, by applying it to everyone equally it makes it fair to all parties.