RN Collection: Mary Lou McDonald. Sinn Fein Vice President, Mary Lou McDonald, will be elected as the new leader and President of Sinn Fein, in February 2018. End.29/2/2008. Sinn Fein Ard Fheis. Mary Lou McDonald urges delegates to vote against the Lisbon Treaty during the opening session of the Sinn Fein Ard Fheis in the RDS in Dublin. Photo: Eamonn Farrell/RollingNews.ie