President of Germany them to the President of the Bundesrat. If the president dies, resigns or is otherwise removed from office, a successor is to be elected within thirty days. Horst Köhler, upon his resignation on May 31, 2010, became the first president to trigger this re-election process. Jens Böhrnsen, President of the Senate and Mayor of the Free Hanseatic City of Bremen and at the time President of the Bundesrat, assumed the powers and duties of head of state. Similarly, when Christian Wulff resigned in 2012, it was Horst Seehofer, Minister-President of Bavaria, as President of the Bundesrat, who assumed the powers
President of Germany within three months. Also, in some cases, a president has signed a law while asking that the political parties refer the case to the Federal Constitutional Court in order to test the law's constitutionality. The Basic Law did not create an office of Vice President, but designated the President of the Bundesrat (by constitutional custom the head of government of one of the sixteen German states, elected by the Bundesrat in a predetermined order of annual alternation) as deputy of the President of Germany (Basic Law, Article 57). If the office of president falls vacant, they temporarily assume the powers