Undeterred by the much-discussed John McCain ad that depicted Barack Obama as little more than an example -- along with Paris Hilton and Britney Spears -- of a celebrity-drenched culture, the presumptive Democratic presidential nominee is celebrating his special day tonight at a gala fundraiser in Boston where Harry Connick Jr. (below) will croon "Happy Birthday" to him (a better choice than a latter-day Marilyn Monroe, we'll give his campaign credit for that).

Obama turned 47 today; later this month (on the Aug. 29), McCain will be 72.

Ever since McCain locked down the Republican presidential nomination, it has been frequently noted that if he triumphs in November, he will be the older than any other president elected to a first term.

Less notice has been paid to another of this campaign's precedent-setting aspects: the largest age difference ever -- 24 years, 11 months and 6 days -- between the two leading White House candidates.

Oddly, what for more than a century had been the biggest gap in ages between candidates -- the 21 years, 8 months and 29 days that separated Democrat James Buchanan (who was the older one) and Republican John Fremont in the 1856 election -- has been shattered twice before in recent cycles.

Bill Clinton was giving away 22 years, 2 months and 7 days to President George H.W. Bush when they squared off in 1992. Four years later, the gap between Clinton and Republican Bob Dole was 23 years, 28 days -- the record that the Obama/McCain contest is surpassing.

One other bit of trivia: The shared August birthdays of Obama and McCain mean that when one of them takes office on Jan. 20, the month will tie November for second place -- with five -- in the producing-presidents department. The other August babies who grew up to become commander in chief were Benjamin Harrison, Herbert Hoover, Lyndon Johnson and Clinton.

The month during which the largest number of presidents have been born? October, with six.

-- Don Frederick

Photo: Associated Press