 WPU campaigned steadily and single-mindedly from 1923 to 1939, along with Senator Lynn Joseph Frazier of North Dakota, for a constitutional amendment that would outlaw war and the preparation for war in the United States and all its territories.WPU refused to negotiate when it came to partial disarmament methods as they completely condemned all acts of violence.From 1926, Rose Henderson, a Canadian social reformer, had become a supporter of the WPU.