Hey, I'm not saying McCain's age is an issue.
But I hear an awful lot of nervous Republicans eager to point out his mother, with her loose mouth and nimble step, is 95, as some sort of genetic bona fide.
Of course, I never hear these same folks point out that when McCain's father was the age McCain is now, he had been dead for two years.
More on the flip if you want to look at the actuarial tables for a hypothetical average 72-year old.
The 2003 actuarial tables from Social Security (the most recent year for which data is available there) are here.
The average 72-year old male has a 3.462 percent chance of dying before his 73rd birthday. For a 71-year old, it's 3.146 percent.
This means that for a person born on, say, 29 August 1936, there is, on average, about a 3.3% chance they will not live to see the next President of the United States be inaugurated on January 20, 2009. There is a 21% chance that a person born on 29 August 1936 won't live to see January, 2013.
Now, this is an average life expectancy. This does not include factors in an individual's favor, such as, say a living parent in his or her 90s or an excellent Congressional health plan which exceeds the benefits and care of 99% of Americans. Nor does it include factors which might be against a person's personal potential lifespan, such as a father who passed away at age 70 or years of stress and starvation.
Also a factor for any candidate, whether they be Democrat or Republican: if they ever smoked, and when they gave it up. I don't know whether have 21-point plans for helping smokers quit is an actuarial factor, though.
So, I don't think age is an issue for a person born on or about 29 August 1936 who might be running for President.