Marsden's commitment to the cause earned her an administrative position in Christabel and Emmeline Pankhurst’s WSPU, for which she left her teaching position in 1909. Although she was dedicated to the early feminist movement, Marsden's strong theoretical principles and independent disposition often brought her into conflict with WSPU leadership, who found her unmanageable. In 1911, Marsden mutually agreed with the Pankhursts to resign her position with the WSPU. Disaffected by the organization, but still committed to the women's movement, she was determined to find ways to support alternative voices relevant to the cause.