Barack Obama's re-election is almost a sure thing, according to U.S. patrons at a Parisian pub.

Canny American expats at Harry's Bar have successfully predicted the outcomes of 17 of the last 19 U.S. presidential races.

This year, the bar's traditional pre-election straw poll gave the nod to Obama, who leads by a narrow margin in several key battleground states.

Manager Alain da Silva says the vote is a time-honoured tradition for his American patrons and says the success rate is because the expatriates have their fingers on the pulse of U.S. politics.

A pulse that's read so accurately that roughly every four years around the first week of November, Harry's Bar can expect a call from the U.S. embassy in Paris unofficially asking how the straw poll went.