RN Collection: Mary Lou McDonald. Sinn Fein Vice President, Mary Lou Mc Donald, will be elected as the new leader and President of Sinn Fein, to succeed Gerry Adams, in February 2018. End. 08/04/2017. Right 2 Water protest. Pictured Deputy Sinn Fein Leader Mary Lou McDonald TD joins thousands of people protest in Dublin city this afternoon against the charging of water. The Protest is trying to keep preassure on the Government to get rid of charging for water and the charges to be dropped against people who took part in water protests in the past. Photo: Sam Boal/Rollingnews.ie