Upon entering the Diet Hirayama commenced a dispute with Tanaka, who was successful in the House of Representatives election and became the party's sole member of that House, concerning the distribution of the party's electoral funds. He soon resigned from the New Party Nippon and later joined the New Party Daichi followed by Green Wind. He contested the 2013 House of Councillors election in the Aichi at-large district but was unsuccessful, finishing in 7th place out of 10 candidates and winning 2.1% of the vote (the top three candidates were elected).