Paul Kirchhof, who was to have been Angela Merkel's finance minister had the conservative Christian Democrats (CDU/CSU) won outright Sunday's general election, announced Monday he was pulling out of active politics in the wake of the election debacle that has left Germany in political limbo. "I'm going to concentrate on my duties as professor for state and tax law," the Heidelberg University professor told the Munich-based daily Abendzeitung in an interview to be published on Tuesday. Conservative challenger Merkel had originally nominated 62-year-old Kirchhof as her future finance minister in the belief that the appointment was a coup that would cement her widely expected victory in the poll on Sunday. Instead, Kirchhof's proposals for a flat tax of 25 percent boomeranged on Merkel, becoming the object of Chancellor Schröder's fierce attacks and eventually slashing the CDU/CSU's lead over Schröder's Social Democrats (SPD) to only three seats in the parliament. Kirchhof said that politicians were likely to develop the suggestions he had made regarding the drastic simplification of Germany's tax system. "And I want to help in that development, but not as an active politician," he said.