sentences:  Thus the Democratic Republican Alliance, the main center-right party after the First World War, had opted for Collaborationism, an option endorsed by its leader Pierre-Étienne Flandin plus other members like Joseph Barthélémy.Furthermore, the political class was considered jointly responsible for the collapse in 1940 of the Third Republic following the disastrous Battle of France, which the historian Marc Bloch later described as the "strange defeat" ("l'étrange défaite").In this way Gaullism and Communism emerged as the most popular political forces in the country.