sentences:  The Cabinet Den Uyl fell on 22 March 1977 after four years of tensions in the coalition and continued to serve in a demissionary capacity.Lubbers was elected as a Member of the House of Representatives after the election of 1972, taking office on 8 June 1977, but as 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 and he subsequently resigned as Member of the House of Representatives on 8 September 1977.Following the cabinet formation of 1977 Lubbers was not given a cabinet post in the new cabinet; the Cabinet Den Uyl was replaced by the Cabinet Van Agt–Wiegel on 19 December 1977.