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. 3/10/2017 Sinn Fein to publish alternative budget proposals.Pictured is 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