Sigmar Hartmut Gabriel is a German politician who was Minister for Foreign Affairs from 2017 to 2018 and Vice-Chancellor of Germany from 2013 to 2018. He was Leader of the Social Democratic Party of Germany (SPD) from 2009 to 2017, which made him the party's longest-serving leader since Willy Brandt. Gabriel is a member of the Seeheimer Kreis, an official internal grouping of the party with liberal economic positions.