Schwimmer took part in the formation of the Woman's Peace Party in 1915, becoming a secretary of the organization. Because of the war, the biennial conference of the International Woman Suffrage Alliance was postponed. Chrystal Macmillan proposed that suffragists should hold a conference to discuss international peace principles and Aletta Jacobs suggested that the Netherlands, as a neutral nation, could host the event. Schwimmer was asked to secure Catt as the chair of the conference but, unable to convince her, she approached social reformer, Jane Addams, who agreed to serve as conference chair. At the International Congress of Women, held in The Hague from 28 April, Schwimmer and Julia Grace Wales, a Canadian academic, proposed a "continuous conference of neutrals" between governments be formed to mediate conflicts and restore peace. During the conference the International Committee of Women for Permanent Peace was established, which would become the Women's International League for Peace and Freedom (WILPF). Schwimmer was selected as one of its board members.