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. 3/10/2009 Lisbon vote. Fine Gael Leader Enda Kenny talks to Sinn Fein's Mary Lou McDonald at Dublin Castle after the second Lisbon Treaty Referendum vote count. Photo. Mark Stedman/RollingNews.ie