On a scholarship of
Robert Bosch Foundation, Lange taught
international relations at
Saint Petersburg State University from 2004 until 2006. From 2006 to 2012 Lange headed the CDU-affiliated
Konrad Adenauer Foundation office in
Kyiv. From 2012 until 2017, Lange led the foundation's domestic policy team in Berlin. In this capacity, he was appointed by CDU Secretary General
Peter Tauber to a commission tasked with drafting proposals for reforming the party between 2013 and 2017. In 2014, he chaired a task force on the future of political parties in Germany. He was also member of a CDU working group committee on domestic policy reforms. After the CDU lost
elections in Baden-Württemberg in 2016, Lange accompanied the party's deputy chairman
Thomas Strobl when he toured the state visiting local chapters and discussing with members. ==Controversy==