He attempted to run for a seat in the House of Representatives during the 2012 general election, but placed second in the Tokyo 8th district and did not win a seat. He then ran an independent campaign (endorsed by the New Socialist Party) to be elected to the House of Councillors in the 2013 election, and was elected on 21 July. He was supported in the election by the People's Life Party, Social Democratic Party and Greens Japan.