German politician and the leader of the Social Democratic Party in Lower Saxony. On 20 January 2013, the SPD and the Green party won the 2013 Lower Saxony state election by one seat. On 19 February 2013, he was elected Minister President of Lower Saxony with the votes of SPD and Alliance '90/The Greens. From 1 November 2013 until 31 October 2014 he was President of the Bundesrat and ex officio deputy to the President of Germany. In November 2017, he was again elected Minister President with the votes of SPD and CDU.