If elected at 72, John McCain would be the old first term president in U.S. history.
"What should we be looking for in our next president? Someone who is really, really, really old," said McCain last week on SNL.
McCain has often poked fun at this age and on Friday he poked fun at the age of the man he expects to run against.
"I admire and respect Senator Obama for a young man with very little experience he's done very well,"
But McCain's age and his eight-year-old bout with melanoma cancer are serious issues for the candidate and the country.
When McCain was diagnosed with a primary melanoma in 2000 his chances of surviving the cancer were about 60 percent.
But Dr. Philip Leboit, co-director of UCSF's dermatopathology service and an expert on melanoma tumors, says the eight year gap is good.
"When someone has a thick melanoma, a serious melanoma, their highest chances of having the disease come back in a lymph node or another organ are in the next couple of years," says Leboit.
An ABC poll shows 70 percent of those asked saying age won't affect their choice. But, 26 percent said McCain's age makes them less enthusiastic. So should he pick an experienced running mate that will ease voters concerns or one that would help him with a swing state?
"All the research on vice presidential candidates suggests the only the one thing they really do help you with is maybe with the state from which they are from," says U.C. Berkeley political scientist Henry Brady
Brady says McCain seems to be going in the swing state direction. This weekend, the Arizona senator is hosting Governors Charlie Crist of Florida, Bobby Jindal of Louisiana and former Massachusetts Governor Mitt Romney.
"But, John McCain may just have to think twice about that because he's got to make sure nobody says 'gosh, if your medical situation deteriorates and there's some problem, who is the person who is going to take over?' That could be important for voters," says Brady.
And so, there is talk about another guest at the McCain ranch this weekend -- Senator Lindsay Graham of South Carolina. He sits on the Senate Armed Services Committee and the Select Committee on Intelligence.