Ada had always since her youth opposed war and becoming a Quaker had fortified her commitment to peace. For her, therefore, 1914 was a catastrophe. She was a founding member of the Women's International League for Peace and Freedom (WILPF) and from 1916 she also worked with Alfred for the No Conscription Fellowship. Although the British government prevented her from attending the Hague peace conference in 1915, she managed to reach Berne, Switzerland, as the representative of the ILP, to attend Third International Socialist Women's Conference which organised opposition to the First World War. There she came up against Lenin, who was determined to get the conference to vote for armed revolution. Ada and the WLL delegate, Margaret Bondfield, stood their ground and Lenin was defeated. At the end of the war she was amongst the British delegations to the Women's International League congresses in Zürich (1919) and Vienna. Her international position was that of the Vienna International, which tried to mediate between the Second International (Labour) and the Third International (Communist) but failed to reconcile them.