Mitt Romney turned 60 today, a personal milestone but also a line of demarcation in the unfolding race for the 2008 Republican presidential nomination.
While the birthday moves the former Massachusetts governor closer to the senior set, it leaves him a relative fountain of youth compared to another leading contender for the GOP nomination.
At 70, Sen. John McCain, R-Ariz., is the oldest major candidate in either the Democratic or Republican primaries. The current GOP front-runner, former New York Mayor Rudy Giuliani, is 63, while the youngest candidate from either party is Democrat Barack Obama. The Illinois senator is 45.
Age and experience
If McCain were elected president, he would be the oldest person ever to assume the presidency. He would be 72 at his inauguration, 76 if he won a second term, and 80 by the time he completed it.
Neither Romney nor Giuliani has overtly exploited McCain's age, but it remains a sensitive subject within the senator's campaign. McCain is a bona fide war hero, but he also cannot raise his arms over his head because of the torture he suffered as a prisoner of war in Vietnam, and his face bears scars from past bouts with skin cancer.
"I think we're expecting people to run for president in their 50s and 60s," said presidential historian Joan Hoff, a Montana State University professor and former head of the Center for the Study of the Presidency in New York.
"By that time, they've had other life experiences that make people think they're seasoned and experienced. McCain is past that mark, and by the same token, age may be a factor against Barack Obama, although a lot of other things go along with his age, including his relative lack of experience," Hoff said.
McCain himself cringed during a Feb. 28 interview with comedian David Letterman, when the talk-show host spent the opening minutes of a conversation with the senator forcing him to talk about his 70th birthday - back on Aug. 29.
Similarly, Rick Davis, one of McCain's top political advisers, grew exasperated this past week when a moderator at a Harvard University forum in which he was participating made note of McCain's age.
Davis went on to note that McCain was particularly popular with younger voters during his first presidential campaign in 2000, despite being 63 at the time.
Age in campaigns
Age played a role in the 1960 campaign between Democrat John F. Kennedy and Republican Richard M. Nixon.
"In 1960, John Kennedy was able to get away with casting himself as part of a 'new generation' even though Richard Nixon was only four years older than him," Hoff said.
Age also resurfaced in 1984, when President Ronald Reagan, a Republican, was being challenged for re-election by Democrat Walter Mondale.
Reagan was the oldest president to hold office. He was 69 at his first inauguration in 1981, 73 at his second inauguration in 1985 and 77 when he left office. After his death in 2004 of complications from Alzheimer's disease, there were questions about whether he was already suffering from the mind-dimming affliction before he left the White House.
Romney, a fanatic about diet and exercise, drew plaudits around the Massachusetts Statehouse one summer when he was photographed shirtless at his New Hampshire lake house, and in 2003, when he and his sons used personal watercraft to rescue six people from a sinking boat.
As for his 60th birthday, no public celebration is planned.