Why do so many US presidents like to say 'I'm Irish'?

Almost every US President since John F Kennedy claims to come from Irish ancestry - and it's not just the White House.Some 45 million Americans claim Irish heritage, 10 times more than the population in Ireland. The two countries have been politically aligned for decades, so why is their relationship so enduring?On the Sky News Daily Sky's senior Ireland correspondent David Blevins with political journalist Aoife Moore are in Belfast to explore what's in it for both countries. Plus David speaks to Dr Richard Johnson, senior lecturer in US policy at Queen Mary about the countries special relationship.Producer: Emma Rae WoodhouseEditor: Philly Beaumont