sentences:  He was considered one of the most important 'green faces' of the GreenLeft.He has initiated some plans for governmental reform, including the temporary law on the referendum, together with Niesco Dubbelboer of the social-democrat PvdA, which was rejected in 2005.He supported a constitutional amendment providing for referendums together with Dubbelboer and Boris van der Ham of the social-liberal D66 party.