Tomenko is a centre-right politician, previously a member of the Yulia Tymoshenko Bloc. He was also one of the leaders and most notable speakers of the Orange Revolution. In 2005, Tomenko served as Vice-Prime Minister of Ukraine in the Cabinet of Yulia Tymoshenko (coordinating humanitarian policy). In the Verkhovna Rada, he also served as the Chairman of the Freedom of Speech and Mass Media Committee and twice as the Deputy Chairman of the Verkhovna Rada (during the 6th and 7th convocations). Tomenko tendered his resignation as deputy Chairman of the Verkhovna Rada on 4 July 2012 as a sign of protest against the way legislation on languages in Ukraine was passed on 3 July 2012.