In the early 1970s, Jambrek was close to the reformist wing of the Slovenian Communist Party, led by Stane Kavčič and Ernest Petrič.
After the authoritarian turn in the Yugoslav Communist Party in 1972-73, which also affected Slovenia, Jambrek withdrew to purely academic work.
Between June and November 2000, he served as Minister of the Interior in the short-lived centre right government of Andrej Bajuk.
[2] Despite never being its member, he was supportive of the Slovenian Democratic Party until October 2011, when he voiced his sympathy for the newly established liberal centrist Gregor Virant's Civic List.
After voicing his support for the Civic List, he was accused of being an agent of the Yugoslav secret police,[4] In an interview published by Planet Siol.net, Jambrek characterized the SDS as a party of "humiliated and insulted class, who never had privileges and who are frustrated because of that"[5][6] He is not involved in politics anymore.