In her youth (1980–1982) Schubert was a member of the German Social Democratic Party's (SPD) youth organization, but later became involved with the extraparliamentary left. In 1996 she started to work in the office of the Party of Democratic Socialism (PDS) in the German Bundestag, and in 2001 she joined the party as a member. The PDS was the successor of the East German communist party "Socialist Unity Party of Germany" (SED) after reforms in 1990. In 2003, Schubert joined the board of the PDS. In connection with the fusion of Die Linkspartei (the name of PDS from 2005) and Labour and Social Justice – The Electoral Alternative (WASG) to form Die Linke, Schubert became one of four vice chairmen of the party, which is led by two chairmen, one from the former Linkspartei and one from the former WASG.
Criminal charges against Wikipedia
On December 6, 2007, in a much-publicized move, Katina Schubert filed criminal charges against German Wikipedia, a German-language online encyclopedia, for featuring Nazi symbols such as the swastika in its articles. In particular, an article on the Nazi youth movement Hitler-Jugend was referred to by Schubert. After criticism from other members of her party, Schubert withdrew her charges but maintained her criticism of Wikipedia.