CBC: The reason for her resignation, which was first reported by iPolitics, is not yet known. Wallin turns 75, the Senate’s mandatory retirement age, in 2028.
…After she became embroiled in the Senate expenses scandal that started in 2013, she was asked to leave the Conservative caucus in the upper chamber.
An audit determined that about $140,000 in expenses she charged to the Senate were improper as they covered travel related to her positions on corporate boards…