The outgoing leader of the National Council of Churches, the Rev. Bob Edgar, has been named head of Common Cause, a national advocacy group. The national governing board of Common Cause announced Tuesday it had elected Edgar president and CEO to succeed Chellie Pingree, a former state legislator from Maine who stepped down in February. Edgar, 63, had said in October that he would not seek a third term as general secretary of the ecumenical and humanitarian group, which represents mainline Protestants, Orthodox and Anglican churches with millions of members. Edgar is a former Democratic congressman who represented the 7th Congressional District of Pennsylvania from 1975 to 1987.