miller was a founding member of the women's equal franchise association, which was established in 1894 and almost immediately suffered a split. leontine cooper left to form the women's suffrage league, alleging that the wefa was too close to the labour movement which could hinder women's enfranchisement. miller remained and was elected president. she held the position until 1905, when the organisation disbanded on the successful attainment of women's suffrage. despite the differences, miller, cooper and the conservative women's christian temperance union often worked together on suffrage issues.