John McCain is 72 years old. If he gets elected, he will be the oldest man ever to be inaugurated as President of the United States. He has numerous diagnosed and treated cancers, but should he survive into a second term he will be pushing 80! Maybe that is why he is running. This is probably the only job he can apply for and hope to get at his advanced age.
Everybody knows that electing a young person does not guarantee that he or she will stay healthy throughout the term, but it is a hell of a lot more likely. ‘Experience’ is just a cover for age.