After he entered the Chamber of Deputies, he became a leading member of the Radical-Socialist Party and was responsible for building the party into a structured modern political party. For most of the interwar period, he was the chief figure of the party's left wing, supporters of a governmental coalition with the socialist Section française de l'Internationale ouvrière (SFIO). A government minister in various posts during the coalition governments between 1924 and 1928, Daladier was instrumental in the Radical-Socialists' break with the SFIO in 1926, the first "Cartel des gauches" with the centre-right Raymond Poincaré in November 1928. In 1930, he unsuccessfully attempted to gain socialist support for a centre-left government in coalition the Radical-Socialist and similar parties. In 1933, despite similar negotiations breaking down, he formed a government of the republican left.