Birgitte Nyborg and Katrine Fonsmark are the central characters of season 4, set 9 years after season 3. Both characters are tested in their new roles of Party leader and news chief, respectively and it doesn't paint a pretty picture. In the three prior seasons both of them took principled, difficult stands that sometimes came at high personal and professional costs for both of them. They were portrayed more heroically in the 3 previous seasons than the final series.
Now they both face difficult choices while in positions of power and find themselves making the same compromises they once decried and criticized while in more subordinate roles. More than once their supposedly important principles take a back seat to expediency and the desire to retain control and position.
We may not enjoy seeing them portrayed this way, but it is a realistic turn of events and the writers are to be congratulated for providing the framework for this transformation and the actors are to be praised for bringing them to life in a believable fashion.
As an American viewer I enjoy getting insight into 4 specific areas: Denmark's parliamentary system; the relationship between the professional Civil Service and elected politicians; the relationship between Denmark and Greenland; and the relationship between Denmark and the Superpowers. Very refreshing and informative. It has the best attributes of 2 long running US series, "West Wing" and "Madame Secretary".