In 1907 Cabete became a freemason, joining the Grand Orient of Portugal Lodge. In 1909, together with Ana de Castro Osório, Carolina Beatriz Ângelo and other feminists who supported the Republican cause, she became one of the founders of the Republican League of Portuguese Women, which both sought the end of the Portuguese monarchy and advocated for women's emancipation and suffrage. As a militant republican, like her husband, she actively participated in the propaganda that preceded the regime change on 5 October 1910.