This week's photos of a shirtless President-elect Barack Obama in Hawaii are not the only time a world leader has bared his abs.

When John F. Kennedy was pictured shirtless, there were media accounts fretting about the threshold we had crossed as a country, said David Greenberg, a professor at Rutgers University who is working on a history of political spin.

“;There was John F. Kennedy by the beach, shirt off, this young, glamorous president,”; Greenberg said. “;So in a way this is 48 years old now that we're having this.”;

Since then we've had Lyndon Johnson lifting his shirt to show reporters his surgery scar and pictures of Ronald Reagan and Bill Clinton in swim trunks.

“;It was kind of an erosion of what had been boundaries of formality between the president and the public,”; Greenberg said. “;We've had 'boxers and briefs' and a real acquaintanceship with a personal side, an uninhibited side, an unclothed side of the president.”;

Combine that with an increasing hunger for celebrity photos and a chiseled presidential body, and Obama becomes an obvious target for paparazzi. Apparently the Obama Girl who was all the rage on the Internet during the early stages of his campaign isn't the only one with a crush.

“;Comments have been 95 percent positive, everything from 'helllooo, president' to a 65-year-old lady who said she had to wait this long to find a president who she finds attractive,”; said Frank Griffin, co-owner of Bauer-Griffin, a photo agency that distributed this week's shirtless Obama photo.

Earlier on his vacation, Obama was cranky as reporters snapped pictures through a chain-link fence and bushes, asking “;OK, guys. Come on. ... How many shots do you need?”;

But such personal shots - dropping the girls off at school, hitting the gym, practicing his golf swing - also serve to humanize the president. Greenberg can see why Obama might allow the beach photos to be taken.

“;I'm sure if he didn't do it on purpose, he's not exactly crying in his coffee about it,”; he said. “;I don't see any down side.”;

Well, maybe one: Might world leaders take the president less seriously if they can picture him in his underwear?

Fortunately, French President Nicolas Sarkozy beat him to it with stripped-down beach photos. Russian Prime Minister Vladimir Putin was pictured shirtless on a fishing expedition.

“;In some ways we're entering a more casual international environment, too,”; Greenberg said. “;But if he's sitting down with Putin, he has to project gravitas.”;

Griffin has submitted his photo agency for credentials for Obama's inauguration on Jan. 20. He said it's too soon to estimate how much Bauer-Griffin will earn from the beach photos “;within tens of thousands or hundreds of thousands.”;