In his maiden speech in the European Parliament, in September 2019, he spoke out against patents on plant characteristics.[5][6]
As a member of the European Parliament, he voted against the new European Commission of president Ursula von der Leyen, because he considered her programme to be too federalist. Later he also voted against the resolution to denounce the LGBT-free zones in Poland, because the resolution called on EU Member States to recognise same-sex marriage. He has also signed a declaration against surrogacy.[7] Ruissen in 2019 was one of the Members of the European Parliament visiting Taiwan, expressing support.[8] In January 2020 he voted against the European Green Deal, proposed by EU commissioner Frans Timmermans, saying in his view the proposal is unrealistic.