“…Overall, social democratic parties, and in some countries, liberal parties, were key actors pushing for comprehensive schooling in the past, while Conservative and Christian-democratic parties belonged to the main defenders of selective schooling (Österman 2017). Tracing the historical roots of national variations in comprehensive schooling in the Scandinavian countries, England and Germany, Wiborg (2009), for example, highlights how different national approaches and the success of reform ambitions were shaped by the power resources and political choices of social democratic parties, including their ability and willingness to forge coalitions with other parties (see also Sass 2015). However, the political divide between left and right has not always been that clear-cut.…”