The spread of St. Patrick's Day celebrations in the U.S. was a way for Irish immigrant communities, who in the 19th century faced discrimination and opposition, to stake that ground, he says: “It’s a kind of immigrant Irish way of combating nativist antagonism against them.”

While St. Patrick’s Day festivities have strayed from their saintly origins, and are now marked by green-dyed food, parades and leprechauns, the holiday remains tied to St. Patr

Photos show how St. Patrick's Day has been celebrated at the White House through the years. As President John F. Kennedy was America's first Irish-Catholic president, St. Patrick's Day held special meaning for him.