sentences:  Zeevalking was elected as a Member of the House of Representatives after the election of 1977, taking office on 8 June 1977 but he was still serving in the cabinet and because of dualism customs in the constitutional convention of Dutch politics he couldn't serve a dual mandate he subsequently resigned as State Secretary for Justice on 8 September 1977.In December 1978 Zeevalking was nominated as Mayor of Rijswijk, he was installed as Mayor, taking office on 16 January 1979 and subsequently resigned as a Member of the House of Representatives on 24 January 1979.Zeevalking also served as Chairman of the Democrats 66 from 27 October 1979 until 11 September 1981.