After the Nineteenth Amendment was ratified and upheld in the 1922 Supreme Court case of Leser v Garnett, Cain and three other women won seats in the Minnesota House of Representatives in the 1922 election. During Cain's single session in office (1923-1924), she co-sponsored a bill about anti-masking, which prevented Ku Klux Klan members from wearing masks or hoods in public (House File No. 138 that became Minnesota Laws of 1923, Chapter 160[3]).[4] This ended up being the first of fifteen similar bills to be passed in the United States.[2]
Post-electoral career and activism
After serving in the state house, she served on the staff of United States Senator Eugene McCarthy of Minnesota.