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.”

Irish nationalist groups active in the U.S. – the Fenians, Clan na Gael and, later, Irish Northern Aid – participated in these American St. Patrick’s Day parades, proudly wearing green to demonstrate their nationalism and the connection to past nationalist groups such as the United Irish.