Pity the poor historian a couple hundred years from now, at a loss to figure out why Barack Obama, an American president at the start of the 21st century, was photographed meeting in the Oval Office with – a pirate.

What kind of unexplained policy initiative was being played out in this photo, the historian might wonder, perhaps confusing it for something other than what it was: a gag – one of dozens – for the president's remarks at the White House Correspondent’s Dinner.

The joke was the idea of three top presidential aides including senior advisor David Axelrod.

They would have Mr. Obama refer to his recent meetings with world leaders.

“There I am with Japanese Prime Minister Taro Aso,” he would say, followed by, “there I am with Gordon Brown.”

But the punch line was his assertion that he was living up to his campaign pledge that “we can’t just talk to our friends.” And with that, up would pop the photo of President Obama with a pirate.