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 in February 2018. End.3/10/2017 Sinn Fein to publish alternative budget proposals. L TO R. Party President Gerry Adams and Deputy Leader Mary Lou McDonald during the launch of Sinn Fein to publish alternative budget proposals at the Davenport Hotel Dublin. Photo Leah Farrell/RollingNews.ie