Every year on March 17th, the Irish Taoiseach (Prime Minister) visits the White House and presents a bowl of Irish shamrock to the U.S. President. It is a tradition that dates back to the 1950's and is a highlight on the Irish American calendar. 

But what really happens in the White House on St. Patrick's Day? We speak to two former Irish Taoisigh (PM's) Enda Kenny and John Bruton, Barack Obama's speechwriter Cody Keenan, historian Dr. Michael Kennedy and broadcaster and author Dearbhail McDonald.