Emma Smith DeVoe was a major figure in the American woman suffrage movement and a Republican Party activist. Although she spent the bulk of her political life in Washington state, she was also a paid suffrage worker on the national level, helping to bring about woman suffrage in Washington in 1910, and the Nineteenth Amendment granting the vote to all American women in 1920. The guiding principle of her campaigns was: "Always be good-natured and cheerful" (Ross-Nazzal, "Emma Smith DeVoe," 76). Her efforts in Washington state were both effective and controversial. The 1909 conventions in Seattle of the Washington Equal Suffrage Association (WESA), of which she was president, and the National American Woman Suffrage Association (NAWSA), for which she was a paid organizer, brought to a head the controversies with the Eastern Washington clubs led by Spokane's May Arkwright Hutton (1860-1915). Despite what some considered DeVoe's heavy-handed leadership style, her overall contribution to the suffrage movement was extraordinary. After ratification of the Nineteenth Amendment, DeVoe entered Republican Party politics, eventually rising to leadership positions on the state and national levels.
In 1880, Emma Smith married John Henry DeVoe, an agent for the Chicago and Alton Railroad. He would prove to be a staunch supporter of her suffrage work. They moved to Huron, Dakota Territory, where both Emma and John DeVoe campaigned for moral reform, temperance, and statehood for the Dakotas, as well as woman suffrage. Under the mentorship of Susan B. Anthony, who campaigned in Dakota Territory, staying with the DeVoes and making their home the headquarters of the suffrage campaign, Emma honed her skills as a public speaker and her image as a feminine, non-confrontational advocate. But, despite the efforts of Anthony and DeVoe, an 1890 South Dakota campaign failed, and women of the state did not achieve the vote until 1918.